Fire in the East

XIII

It was dark under the high barrelled arch of the Palmyrene Gate. The outer gate was still closed and, although the inner was open, little light found its way in. The larger-than-life personification of the Tyche of Arete painted on the northern wall was nothing but a blur to Turpio, and he could see nothing of the graffiti thanking her for safe journeys he knew to be scrawled below.

Turpio had always had a particularly developed sense of smell. The prevailing smell here was of the cool, possibly even damp, dust which lay in the shade of the gatehouse and which the sun never reached. There was also the smell of the worked wood of the great gate in front of him and, surprising because it was so out of context, there was a strong, a very strong scent of perfume: oil of myrrh. The hinges of the gate were soaked in it to prevent them squeaking.

Turpio was tense, but he was glad to be there in the dark waiting to lead the raid. He had had to argue his case hard in the consilium. Acilius Glabrio had pointed out that two centuries of his legionaries amounted to 140 men, while two turmae of Turpio's auxiliaries came only to 72 troopers so, in fairness, it should be Acilius Glabrio himself who commanded. Turpio had been reduced to appealing to Ballista on the grounds that, while the northerner could not afford to risk the patrician commander of the legionaries in his garrison, an ex-centurion who commanded auxiliaries was more expendable. Eventually the Dux Ripae had given his assent.

Turpio was aware that everyone in the consilium had known why he was just so keen to lead this raid: he still needed to prove his worth after the stain that Scribonius Mucianus had left on his character. Over the winter he had trained Cohors XX well. Certainly there was no corruption now. It was an efficient unit, a unit of which one could be proud. But if Turpio were to do well here in Arete, win the trust of Ballista, do everything that he wanted, he needed more. He needed a chance to prove himself in action. What could be better than a straightforward, desperate night raid into the heart of the enemy camp? Of course the risks were enormous, but so was the possibility of glory. 'Decapitate the Persian reptile. Aim for the huge purple tent in the centre of the Sassanid camp. Catch the King of Kings sleeping or with his baggy trousers down. Bring me his head. No one will ever forget your name.' Turpio was not the only one to have been stirred by Ballista's words.

Turpio detected another scent – cloves, or possibly carnations; a clean pleasant smell. It had to be Acilius Glabrio. The young patrician moved slowly, carefully, along the passageway. Turpio spoke his name quietly and held out his hand. The two men shook hands. Acilius Glabrio handed over some burnt cork, wished Turpio good luck, and left. As Turpio blackened his face and forearms, he wondered if he had misjudged the young nobleman.

He smiled to himself in the dark. No, he had not totally misjudged him. The young nobleman was still a prick. Turpio could feel laughter bubbling up in his chest as he thought of the meeting of the consilium. When Ballista walked in Acilius Glabrio had approached him full of patrician self-importance. 'A word if you please, Dux Ripae.' The northerner had slowly turned on him his unsettling barbarian blue eyes. He looked as if he had never seen the speaker before. His reply had been couched in terms of the frostiest civility: 'With pleasure, Tribunus Laticlavius, in just a moment.' Ballista had asked his new standard-bearer, Antigonus, to attend him and had led the Batavian to the far corner of the room. There he had spoken in low, emphatic sentences. At the end Antigonus had saluted and left. Walking back, Ballista's face was open and guileless. 'What was it you wanted, Tribunus Laticlavius?' The wind having been taken from his sails, the fuming young patrician had muttered that it could wait.

A muted commotion in the passageway behind Turpio indicated the approach of the Dux Ripae. Against the gloom, the greater darkness of the northerner's height and bulk, the strange bird crest above his helm could just be distinguished. The northerner seemed to have no smell at all. In his heightened, pre-battle state, Turpio wondered for a moment if that were like casting no shadow.

'Everything is ready. Time to go,' Ballista said quietly.

'We will do what is ordered, and at every command we will be ready.'

They shook hands. Ballista half turned, raised his voice slightly. 'Try not to get too many of the boys killed.' The nearer soldiers chuckled. Turning back, Ballista dropped his voice. 'Remember, Turpio – straight in and straight out. If you reach Shapur's tent, excellent, but if not no problem. Do not get into a fight. You have a couple of hundred men. They have about 50,000. If you can, surprise them, kill a few, burn a few tents, shake them up. But then get out quickly. Do not get trapped. At the first sign of organized resistance, head for home.' They shook hands again. Ballista stepped back to the side of the passage just below the pale shape of the Tyche. He called softly over the heads of the waiting soldiers.

'Time to go, boys, time to start the venationes, the beast-hunts.'

Despite the oil of myrrh the gates seemed to creak alarmingly as they ponderously opened. Turpio set off.

As good luck would have it, it was the night before the new moon. Yet even lit just by starlight, the western plain looked very bright after the darkness of the gate. The road shone very white as it stretched arrow-straight ahead. The flickering campfires of the Persians seemed infinitely distant.

For a time Turpio just concentrated on walking quickly. Soon he was breathing more deeply. The road under his feet felt smooth but unnaturally hard. Behind him the 140 legionaries of Legio IIII Scythica marched as quietly as Roman soldiers could. They were not talking and were taking care not to clash their weapons and armour. Some had even tied rags around their military boots to deaden the sound of their hobnails. Yet there was a steady series of small chinking sounds. Nothing could ever completely persuade Roman soldiers of the necessity of removing all the good-luck charms from their belts.

Once he had remembered to do so, Turpio counted off 200 paces and then stepped to one side and looked around to take stock. Ten wide and fourteen deep, the small column of legionaries appeared tiny in the immensity of the plain. Turpio looked back at the town. True to his word, Ballista had managed to persuade the priests to organize a religious ceremony at the Temple of Bel. Designed to draw any sleepless Sassanid eyes and ears, a big procession with bright lights and loud chanting was making its way slowly along the extreme northern end of the city wall. To help the raiding party orientate itself, a single torch burnt over the Palmyrene Gate and another on the last tower to the south. The rest of the wall was in darkness.

Turpio had to run to regain his position at the front of the column. Like him, the legionaries wore dark clothes and had blackened their equipment and exposed skin. To Turpio, they seemed hideously exposed on the gleaming white road.

Ahead, quite widely separated individual fires marked the Sassanid picket line. Behind them was the more general glow of the camp, spreading as far as the eye could see. The picket lines suddenly were much nearer. Surely the Persian sentries could not fail to notice the legionaries? Turpio's own breathing seemed loud enough to carry across the plain and wake the dead.

Nearer and nearer to the picket on the road. Turpio could make out the single rope tethering the nearest horse, individual flames in the fire, dark shapes swathed in blankets on the ground. Without a word he broke into a run, faster and faster, drawing his sword. Close behind him heavy footfalls, laboured breathing.

Turpio vaulted over the first sleeping sentry and swerved around the fire to reach the far side of the picket. The sentry nearest the Sassanid camp sat up, his mouth forming an 'O' to shout, and Turpio smashed his spatha down on his head with all his force. It needed a boot on the man's shoulder to withdraw the blade. Behind, a brief flurry of grunts, cut-off yells and a series of sounds that always reminded Turpio of knives cutting through cabbages. Then near-silence. Just 140 men panting.

He took stock. There were no shouts, no trumpet calls, no shadowy figures fleeing across the dark plain to raise the alarm. The nearest picket fires on either side were at least a hundred paces away. There was no movement around them. All was quiet. Ballista had been right; the big barbarian bastard had been right. The Sassanids lacked discipline, good old-fashioned Roman disciplina. Tired after the march, contemptuous of the small numbers of soldiers against them, the Persian pickets had laid down to sleep. The first night of the siege, and no Sassanid nobleman had yet taken it on himself to impose a routine.

Turpio mastered his breathing and called softly. 'First Century, form testudo.' He waited for the shuffling to subside and a dense knot of overlapping shields to form. 'Second Century to me.' More shuffling, then silence. 'Antoninus Prior, make the signal to the Dux.' The centurion merely grunted, and three legionaries detached themselves from the*testudo. There was a brief flurry of activity and three lanterns hung in a row, their blue-leaded lights winking their message back across the plain.

Turpio turned to the column of the second century drawn up close behind him. 'Swords and torches to hand, boys.' Turpio looked at the Sassanid camp and at the royal tent looming up massive in its centre. He spoke to the centurion beside him. 'Ready, Antoninus Posterior? Then let's go and decapitate the reptile.'

Ballista had been waiting to see the signal. How he had been waiting. When the two centuries had set off down the road they had looked horribly exposed, surely visible for miles. But soon they had become an indistinct moving blur then vanished into the dark. Time's arrow had gone into reverse. Ballista prayed that he had not sent them all to their deaths. The noises of the two waiting turmae of cavalry had floated up to him on the roof of the gatehouse; the jingle of a bridle, the stamp of a hoof, a horse coughing abrupt and loud.

The three blue lights appeared. Ballista's heart leapt. So far so good. Demetrius whispered the name of the senior decurion in his ear. Ballista leant over the battlements. 'Paulinus, time to go. Good luck.'

Seventy-two horsemen in two columns, the turmae of Paulinus and Apollonius, clattered out into the night one after another, quickly picking up speed. They also vanished into the moonless night.

Time dragged.

Allfather, Deep Hood, Raider, Spear-Thruster, Death-Blinder, do not let me have sent them all to their deaths. Do not let them be killed in the darkness out there Like Romulus. Yet so far the plan was going well. To avert the evil eye, Ballista started to clench his fist, thumb between index and forefinger. If this carried on he would end up as superstitious as Demetrius. He completed the gesture anyway.

The plan was straightforward. Having overwhelmed the picket on the road, one century of legionaries was to remain there to cover the retreat, while the other century aimed for the jugular, rushing into the enemy camp, aiming to cut their way into the very tent of the King of Kings. To help them by spreading maximum confusion, the two turmae of cavalry were to fan out left and right and ride between the picket lines and the Sassanid camp proper shooting fire arrows at everything in sight. The turma heading south, that of Paulinus, was to make its escape by descending into the southern ravine and riding all the way to the wicket gate by the Euphrates. If any Persians were foolish enough to follow them down into the ravine, so much the worse for them. Hundreds of paces of bad going exposed to missiles from the walls of Arete would deal with them. The other turma, that of Apollonius, had a trickier task. It was to ride north for a short way then turn about and form up on the road back to town to aid the century which was to cover the retreat.

The plan had seemed so straightforward in the meeting of the consilium. Ballista was praying that it would not all become terribly confused and fall apart in the terrifying reality of a dark night.

Time continued to drag. Just when Ballista was beginning to wonder how much longer the hiatus could possibly last, someone needlessly called out – There! There! – and was promptly shushed. Lights could be seen moving in the heart of the Sassanid camp. The first fragmented sounds of alarm drifted back to the town of Arete. Turpio and the legionaries were about the real work of the night, just seventy men challenging the beast in its lair.

Now things were speeding up. Time's arrow had resumed its course. Events came tumbling one after another. Ballista could see yellow flames winking into life as the troopers of the turmae kindled their torches from the picket fire directly ahead. Then two strings of torches could be seen moving fast away from the centre of the Persian camp, one north, one south. The first fire arrows were arcing through the sky. Like a beast angered at being disturbed from sleep, a great roaring came from the Sassanid camp. The noise rolled across the plain to those on the high walls and towers of Arete.

More and more lights – red, yellow, white – flickered into life as fire arrows, thrown torches and kicked-over lamps set fire to tents, soft bedding, stacked fodder, piled-up provisions, jars of oil. Shapes flitted across the fires, gone too quickly to tell what they were. The noise, like that of a great forest fire, bounced back and forth around the plain. Above the general background rose sharp screams, human and animal, and the strident call of trumpets attempting to restore some order to the Persian horde.

As Ballista watched, the string of lights heading south winked out one by one. This should be a good sign – Paulinus's troopers jettisoning the last of their torches and riding hell for leather through the darkness for safety. But, of course, it could be bad- the Sassanids surging around them, cutting them down. Even if it were good, the turma was far from home safe. Riding flat out on a moonless night, would they find the entrance to the ravine? It had been an easy enough descent for Ballista and four others at a comfortable pace on a bright, sunlit day, but they had dismounted. It might be a very different proposition for nervous men on panting, labouring horses in the pitch dark.

By the time Ballista looked to the north the chain of lights that marked Apollonius's turma had also vanished. Hauled from their horses by blades and hands or riding unmolested to their rendez-vous, there was no way of telling.

Allfather, The Wakeful, The Wanderer, The Crier of the Gods, what is happening? What of Turpio?

Roaring. Head far back, roaring, laughing. Turpio had seldom felt so happy. It was not the killing, not that he had any objection to killing: it was the sheer ease of it all. The first thing they had come to in the camp was the horse line of a unit. It had been the work of moments to cut the tethers, slap the horses with the flat of their blades and send them stampeding ahead into the camp. Consternation spread rapidly as the animals thundered through the tightly packed tents, overturning cooking pots, bringing down small tents. A Persian head appeared from one. A swing of Turpio's spatha and the head fell back bloodied.

Yelling at his men to keep together, Turpio pounded through the Sassanid camp. Once, a guy rope caught his foot and he went sprawling on his face. The metal-studded sole of the boot of one of his own men stamped into his back before strong arms dragged him to his feet and they were off again. Pounding through the camp, trying always to keep the looming royal tent in sight. Isolated Persians, individuals or- small groups, popped into view. They ran or fell where they stood. There was no organized opposition.

In what seemed no time they were there. Several large standards hung limply from tall poles. Half a dozen guards, their gilded armour glinting in the light of the fires, made a stand in front of the huge purple tent. Leaving some of the legionaries to deal with them, Turpio ran a few yards to one side and used his blade to slice through the side of the tent. He emerged into what appeared to be a corridor. Rather than follow it, he cut through the inner wall. Now he was in an empty dining room. Some of the remains of the evening meal had not been cleared away. Turpio swept up a drinking flagon and tucked it safely in his belt.

'No time for looting,' he bellowed and, swinging his spatha, tore through the next wall. This time he emerged into pandemonium – high-pitched screams, female voices. He swung round, knees bent, sword at the ready, seeking out any threat, trying to make sense of the sweet-smelling, soft-lit room.

'Fuck me, it's the King's harem,' said a legionary.

Women and girls wherever one looked. Dozens of beautiful girls. Dark, blond. Clad in silk, kohl round their eyes, cowering in corners, behind pieces of soft furniture, they called out in Persian. Turpio could not tell if they were calling for help or begging to be spared.

'I must be dead and in the Elysian fields,' said a legionary.

Looking round, Turpio spotted an ornate doorway. A fat eunuch dithered indecisively in front of it. Turpio kicked him out of the way. Shouting for the legionaries to follow him, he dived through the opening.

The room was nearly dark. It was empty. There was a smell of balsam, a smell of sex. Turpio went over to the wide, rumpled bed. He put his hand on the sheets. They were warm. Jupiter Optimus Maximus, we were thatfucking close.

A small movement caught the corner of Turpio's eye. In a flash, he whirled his sword out. The girl was in the corner of the room, trying to hide behind a sheet. Her eyes were very wide. She was naked. Turpio smiled, then realized it might not be altogether reassuring.

Tyche! A few moments earlier and everything would have been different. Turpio noticed a gold bangle on the bed. Without thought he picked it up and slid it on his wrist. Tyche.

His reflective mood was shattered when a legionary barrelled through the door. 'The bastards are coming for us, Dominus.'

Outside, a group of Sassanid clibanarii on foot had banded together. They were edging forwards from the right. A tall nobleman was haranguing them.

'Close ranks.' As soon as he sensed the legionaries around him, Turpio filled his lungs and began the call and response. 'Are you ready for war?'

'Ready!'

'Are you ready for war?'

On the third response and with no hesitation the legionaries surged forward. Turpio saw a shiver run through the enemy ranks. Some of them edged sideways, trying to get closer into the protection of the shield of the man on their right. Some gave a step or two backwards.

Excellent, thought Turpio. Momentum against cohesion, the age-old equation of battle. We have momentum, and they have just sacrificed their cohesion. Thank the gods.

Tucking his shoulder into his shield, Turpio slammed into one of the enemy. The Sassanid staggered back, knocking the man behind him off balance as well. Turpio brought his spatha down on the first man's helmet. The helmet did not break, but it buckled, and the man fell like a stone. The next man gave ground. Turpio lunged forward. The man gave more.

'Hold your position. Re-form the line. Now, keep facing the reptiles, and step back. Step by step. No hurry. No panic.'

The Sassanids stayed where they were. The gap between the combatants widened. Soon the legionaries were back where they had entered the king's pavilion. Turpio ordered the nearest musician, a bucinator, to sound the recall.

'Right, boys, on my command we turn around and get out of here at the double.'

Getting out of the Sassanid camp was harder than getting in. There was no organized pursuit, no systematic resistance, the camp was in uproar – but this time the Persians were awake. Three times, smallish ad hoc bands of Sassanid warriors, twenty or thirty men, blocked their path and made a stand. Each time the Romans had to check, re-form, charge and fight hard for some moments before they could resume their escape. Once, Turpio called a halt because he feared that they were lost. He had himself hoisted up on a shield. When he could see in which direction the walls of Arete lay, they resumed their headlong flight. On and on they pounded, down the alleyways formed by thousands of close-packed tents. Sometimes they turned left or right; usually they just forged straight ahead. Out of the gloom whistled missiles launched by both soldiers and camp followers. Now and then a man went down. Turpio affected to ignore the swift rise and fall of a Roman spatha when it dealt with those too wounded to keep up. Legio IIII Scythica was not leaving her own to be tortured by the enemy.

At last there were no more tents in front. There was the road to Arete, just off to the left, and there, about one hundred paces down, was the picket fire behind which waited their friends, the century of Antoninus Prior supported by the turma of Apollonius. Turpio and his men seemed to cover the ground in no time.

Turpio rattled out orders, his voice rough from shouting. The raiding party, the century of Antoninus Posterior, was to carry straight on, stick together but make all speed to the Palmyrene Gate. They had done more than enough for one night. Turpio joined the other century. In moments he had Antoninus Prior redeploy it from testudo to a line ten wide and seven deep. Then they set off towards safety at the double, the cavalrymen of the turma of Apollonius trotting about fifty paces ahead, ready to shoot over the heads of the legionaries at any approaching threat.

Four hundred paces. Just 400 paces to safety. Turpio started to count, lost his place, started again, gave up. He had taken his place in the rear rank which, when the enemy caught them, would be the front. Over his shoulder he saw the first dark shapes of horsemen leaving the camp, spurring after them. There would be no chance of reaching the gate unmolested. Ahead, still at some distance, he could see through the gloom hard by the side of the road the short stretch of wall that Ballista had left standing and painted white. It marked 200 paces, the limit of accurate effective artillery shooting from the walls. More important now for Turpio, the ground on either side of the road for the last 200 paces was sown with a myriad of traps. If they could reach that white wall they would be a little bit safer. From then on, the Persian cavalry could only charge them straight down the road. Out here there were but a few pits and caltrops. Out here it was possible for the enemy to outflank then surround them.

Looking back, Turpio saw that the Sassanid horsemen had coalesced into two groups. One was forming up on the road, the other setting off to the north in a wide sweep that would bring them behind the fleeing Romans. There looked to be at least two or three hundred horsemen in each unit. More cavalry were emerging from the camp all the time.

Turpio ordered a halt. The cavalry on the road were moving forward. They were going to charge without waiting for the outflanking manoeuvre to be completed. The legionaries turned to face their pursuers. With a high trumpet blast the Persians put spurs to their horses and came on. These were clibanarii, the Sassanid elite heavy cavalry. Backlit by the fires in the Persian camp, they looked magnificent. For the most part, the men had had time to put on their own armour – it flashed and flickered – but not that of their horses. They came on, moving from a canter to a loose gallop. Turpio could feel the thunder of the hooves of their huge Nisean chargers reverberating up from the ground. He sensed the legionaries around him just begin to waver. Gods below, but it was hard to stand up to a charge of cavalry. In a moment or two some of the legionaries might flinch, open gaps in the line, and then it would all be over. The clibanarii would be in amongst them, horses sending men flying, long cavalry swords scything down.

'Hold your positions. Keep the line unbroken.' Turpio did not think it would do much good. The enormous Nisean horses were getting larger by the second.

Over the heads of the legionaries whistled the arrows of Apollonius's troopers. At least they have not abandoned us, thought Turpio. We will not die alone.

A lucky arrow must have hit a vital part of a Sassanid horse. It fell, skidding forwards and sideways. Its rider was thrown over its head. He remained airborne for an improbably long time before smashing into the road, his armour ringing and clattering around him. The horse took out the legs of its neighbour. It too went crashing. The horse on the other side swerved away and barged into the next horse, which lost its footing. The second rank of horses could not stop quickly enough. They had no option but to plough into the fallen. Within moments, the magnificent charge had been transformed into a tipping, thrashing line of chaos, of men and horses writhing in pain and surprise.

'About turn, at the double, let's get as far from them as possible.' They would have to sort the chaos out. It had bought Turpio and his men a few moments, a few yards nearer to safety.

Jogging down the road, Turpio anxiously looked to his left to see what had become of the party of Sassanid cavalry riding to outflank his men from the north. He could see no sign. He felt his fear rising. Hercules' hairy arse, how could they have got between us and the gate so quickly? Then his spirits lifted. They were not between Turpio and the gate; they were drawing off towards their camp. A group of figures with torches looking down at a fallen horse indicated why. A single horse had fallen into one of the sparse traps set in the band between 200 and 400 paces from the wall. A single horse had fallen, and they had given up.

Now there was only one threat to face. But probably it was too much. Turpio felt that, the next time Sassanid clibanarii thundered down the road at them, the legionaries would break. It had been a very long, frightening night. Men's nerves can only take so much.

'Halt. About turn. Prepare to receive cavalry.'

This time the clibanarii were taking their time. They had formed up in a column seven wide, and Turpio could not see how many men deep. The front rank consisted of seven who had somehow found the time to armour their horses as well as themselves. They were riding knee to knee, big men on big horses. They formed a solid wall of iron, hardened leather, animal horn, the chilling steel points of their lances catching the starlight above them.

Turpio felt a ripple run through the legionaries around him. He could hear feet shuffling nervously, hobnails scraping on the surface of the road. The man on his right was glancing back over his shoulder, looking at the safety of the town. Turpio caught the rank smell of fear. Theirs or his, he was not sure.

'Hold the line. Keep steady. Stand tall. Horses will not run into formed infantry.' Turpio was shouting himself hoarse. He would not be able to speak tomorrow. He grinned as the other unfortunate implication of this struck him. He turned to encourage the ranks behind him.

'If we don't budge they cannot touch us. Keep the line and we will be all right.' Jupiter's bollocks, but the gate looked close. Anyone could imagine turning, running and getting into safety. It was only about 150 paces away. So near you felt you could be there in a moment. 'Do not think of running. You cannot outrun a horse. Run and you are dead. Hold the line and we all live.' The men were not meeting his eye; it was not going to work.

A trumpet shrilled, cutting through the ambient noise of the disturbed night. The clibanarii dipped their awful lances and began to advance down the road at a walk. There was the jingle of armour, the ringing of their horses' hooves on the road, but no sound of humanity. They came on like a long serpent, scale-armoured and implacable.

Twang – slide – thump. The noise of a ballista shooting. Twang – slide – thump. Another. Then another. Louder than anything in the night, all the artillery on the western wall of the town of Arete was shooting – shooting blind into the dark night.

A terrible silence after the first volley. The clibanarii stopped. The legionaries froze. Everyone knew that the ballistae were reloading, the greased winches turning, the ratchets clicking, the torsion springs tightening. Everyone knew that within a minute at most the ballistae would shoot again, that again with superhuman speed and power, missiles would rain down across the plain, falling on friend and foe alike.

Twang – slide – thump. The first of the second round of ballistae was heard. 'Stand up. Stand up. Stand your ground.' Turpio's men were cowering, shields held pathetically above their heads in a useless attempt to protect them from incoming artillery bolts or stones.

Turpio turned to look down the road at the Sassanids, and started to laugh.

'Right, boys, now get up and RUN!'

There was a shocked pause, then they all realized that the clibanarii were cantering away into the night, back to their camp, out of range of the artillery on the walls of Arete. The legionaries turned and ran.

Turpio saw Ballista waiting in the gateway. The torchlight made the northerner's long hair shine golden. He was smiling. As he ran up to him, Turpio again started laughing. They shook hands. They hugged. Turpio was slapping his Dux on the back.

'Brilliant. Absolutely fucking brilliant,' Turpio panted.

Ballista tipped his head back and laughed. 'Thank you. I liked it. Not such a stupid northern barbarian then?'

'Brilliant… mind you, obviously I realized straight away that the ballistae were not loaded, that the mere sound would scare the reptiles off.'

The young optio was prepared to be most helpful. The matter reflected well on Legio IIII Scythica, and it reflected well on the young optio. The latter was a not inconsiderable factor for a junior officer with a career to make.

'Gaius Licinius Prosper, of the vexillatio of Legio IIII Scythica, Optio of the Century of Marinus Posterior. We will do what is ordered, and at every command we will be ready.' The salute was smart.

'Tell me exactly what happened.' Ballista returned the salute. Almost certainly the 'exactly' was redundant. Prosper clearly intended to have his moment, to take his time telling the story before he would lead them to the corpse. Ballista sniffed. He could smell the corpse, or at least what had killed him, from here.

'Last night, as the turma of Apollonius was withdrawn from guard duties at the military granaries so that it could take part in the raid on the Sassanid camp – many congratulations on the success of the raid, Dominus, a piece of daring worthy of Julius Caesar himself, or of -'

'Thank you.' Ballista spoke quickly before they were sidetracked into lengthy comparisons between himself and any daring generals from Rome's past whom the optio could recall. 'Thank you very much. Please continue.'

'Of course, Dominus. As I was saying… as the turrna ofApollonius was not guarding the granaries, you ordered Acilius Glabrio to select thirty-two legionaries drawn from the centuries of Naso, Marinus Prior, Marinus Posterior and Pudens to take over the guard duties.' Ballista stifled a yawn. It was the third hour of daylight. He had had no sleep the previous night and, now the excitement of the raid had drained out of him, he was very tired. 'You did me the honour of choosing me to be the optio in command of the guard detail.'

Ballista was careful not to smile. He had merely told Acilius Glabrio to put a small but adequate guard on the granaries last night. Until a few moments ago he had not been aware of the existence of the young optio. It is easy to collapse all hierarchies above oneself into one almost undifferentiated rank, to assume that your superiors know each other and that your commander-in-chief knows about you. 'You have more than repaid that honour by your diligence,' he said. 'Now please tell me what happened.'

The youth smiled broadly. 'Well, I thought it best to station two legionaries at the doors at each end of the granaries. I thought that, if there were always two legionaries together, there would be far less risk of them being overpowered or one of them falling asleep.' He looked suddenly embarrassed. 'Not that legionaries of IIII Scythica would ever fall asleep on guard duty.'

No, but I might at any moment, if you don't get a move on. Ballista smiled. 'Very good,' he said encouragingly.

'Of course this left only myself as a mobile patrol.'

Ballista reflected that the young optio – Prosper, must remember his name – might recount a lot of information that was unnecessary, but that was better than one of those tongue-tied witnesses you were always having to prompt and chivvy along, especially when he was as dog-tired as he was now.

'I first saw him in the fourth watch, at the end of the tenth hour of the night, just before you had the artillery shoot, when I was proceeding south towards the palace of the Dux Ripae, that is, towards your palace.' Ballista nodded weightily as if at the insight that he was the Dux Ripae and the palace was his. At least they were finally getting somewhere. 'He was walking north between the town wall and the eastern four granaries. Of course there is a curfew, so he should not have been there anyway. Yet there are always soldiers or their slaves out and about at night. He was dressed as a soldier – tunic, trousers, boots, sword belt – but I was suspicious. Why would a soldier be off duty last night of all nights? And he looked wrong somehow. Now I realize it was his beard and hair. They were far too long. No centurion would have let him get away with it, not even in an auxiliary unit. Not that you could tell now, not with the condition he is in.' The young man shuddered slightly.

'And he was acting suspiciously. He was holding a big jar in one hand, holding it away from his body, as if it were very precious, as if he were terrified of spilling a drop. And he was holding a shuttered lantern in the other hand. Again holding it unnaturally far from his body.'

'Excellent observation, Optio.'

'Thank you, Dominus.' The optio was in full flow now. 'As I walked towards him he saw me and turned into the gap between the first and second granaries. I called for him to stop, but he ignored me. I shouted the alarm. I ran after him and yelled to the legionaries on guard at the other end that there was an enemy coming down the eavesdrip and to cut him off.' The young optio paused as if to take questions. None came. He continued. 'When I turned into the alley I could not see him at first. I could see Piso and Fonteius blocking the far end, but he was out of sight. I knew that he must be hiding in one of the alcoves formed by the big buttresses of the granaries.'

One of those alcoves in which Bagoas had been beaten up, thought Ballista.

'As he was cornered, I thought that he might be dangerous. So I called Scaurus from my end to come with me. We drew our swords and started off very cautiously down the alley.' Ballista nodded to indicate that the course of action was both thoughtful and courageous. 'It was very dark. So we were going slowly, covering both sides, waiting to be attacked. Suddenly there is a noise of splintering wood up ahead. Then I am almost blinded by a bright light two alcoves down. There is a sort of whooshing sound, and a ghastly smell. When we can see again, we run forward. Piso and Fonteius are running towards us from the far end. We all get there at once. I will never forget it. Never.' He stopped talking.

'Optio?'

'Sorry, Dominus. It was horrible. I hope I never see anything like it again.'

'Please continue.'

'The bastard was crawling into the little ventilation opening at the foot of the wall. I don't know if he got stuck or if the pain stopped him, but he was just sort of writhing when we got there, writhing and screaming. Never heard anything like it. He must have torn away the wooden slats over the ventilator with his sword, emptied the jar of naptha over himself and, with the lantern, quite deliberately set light to himself. Then he tried to crawl into the ventilator. He turned himself into a human missile. It smelt like… like roast pork.'

'What did you do?'

'There were flames everywhere. The naptha had set the remains of the ventilator on fire. There were flames licking up the brick walls. Even the mud around him seemed to be on fire. Gods below, it was hot. It looked as if it would spread into the granary, get in the ventilator and under the wooden floor. The whole place was about to go up. It was Scaurus who thought what to do. He got his entrenching tool, stuck it in the poor bastard's thigh, and dragged him to the middle of the alley, where we left him. We threw soil on the fires until they were smothered.'

The young optio led Ballista down the alley and introduced him to the legionaries Scaurus, Piso and Fonteius. The northerner praised them all, especially the rather singed Scaurus, and promised they would be rewarded. He asked Demetrius to make a note of it. The Greek boy was looking sick.

The scene was as Ballista had expected. The corpse was twisted, shrivelled, its hair and clothing gone, its features melted. Beyond the fact that he had been a short man, the corpse was completely unrecognizable. The optio was right: disgustingly, it smelt of roast pork. It smelt of Aquileia. It had an entrenching tool, the wooden handle burnt away, sticking out of its leg.

'Did you find anything interesting on the body?'

'Nothing, Dominus.'

Ballista crouched next to the corpse, willing his gorge down. The man's sword was a military-issue spatha. It signified little. There were many available on the open market. The man's boots did not have hobnails, but nor did the boots of a lot of soldiers these days.

'You were right. He was not a soldier.' Ballista grinned. 'Nothing can persuade a soldier to take his ornaments, awards for valour, his lucky charms off his sword belt. All that is left of this man's belt is the buckle.' The northerner pointed to an unremarkable buckle in the shape of a fish. 'Definitely not a soldier.'

From a little way away came the sound of retching. Demetrius was throwing up.

'What could make a man do such a thing?' the young optio asked.

Ballista shook his head. 'I cannot begin to imagine.'

Everyone was waiting for the sun to rise. Already the eastern sky was a pale bronze. A cool steady breeze blew from the south. Ducks were flighting over the Euphrates and the smell of baking bread wafted around the town. If you did not look too far away or you kept your eyes on the heavens, you could imagine that Arete was at peace.

One glance over the battlements shattered any pacific illusions. True as the light advanced, the western desert for once showed green. There were grasses and wild flowers in every little depression. Birds sang. But beyond the delicate spring scene was a black line about a thousand paces wide. The Sassanid host stood shoulder to shoulder. Thirty, forty ranks deep, it was impossible to tell. Above their heads the south wind tugged at the banners. Serpents, wolves, bears, abstract symbols of fire, of righteousness, of Mazda, snapped in the breeze.

Behind the ranks of men loomed the instruments of war. A line of siege mantlets, tall shields mounted on wheels, could be made out running almost the length of the force. Here and there the wooden frames of ballistae stuck up; the keenest eyes counted at least twenty of them. And there, quite widely spaced and unmistakable behind the line, were the City Takers, the three tall, tall siege towers.

Ballista was impressed despite himself. It was just seven days since the Persian horde had descended on Arete. They had found nothing useable; there was no timber for miles: Ballista's men had stripped the countryside in advance. It had done no good. The Sassanids had brought with them everything they needed. Somehow they had transported upriver all the instruments of siege warfare in prefabricated form, almost ready to use. For six days they had laboured. Now, on the seventh day, they were ready. Although he would not admit it to anyone else, would barely concede it to himself, Ballista was worried. These Sassanids were like no barbarians he had fought before. Goths, Sarmatians, Hibernians or Moors-none could have done such things, none could prosecute a siege with such vigour.

Ballista and the defenders had not been idle in the seven days since the night raid. Turpio's foray may have failed to kill Shapur but still must be counted a success. Roman casualties had been very light. Five troopers were missing from the turma of Paulinus, none at all from that of Apollonius. Of the legionaries, there were twenty empty places in the century that had actually entered the Persian camp, that of Antoninus Posterior, and one from that of Antoninus Prior – oddly, as it had not actually been engaged. The latter, although no one said so out loud, was widely considered to have deserted. Overall the raid had raised Roman morale, and it was safely assumed to have shaken that of the Persians. Yet such a large-scale raid had not been repeated. Ballista knew that the Sassanids would now be on guard. He was waiting for the next phase of the siege, the next predictable turn of the dance. He was waiting for an all-out Persian assault.

The Romans had not made another big foray yet the Sassanids were unlikely to have been sleeping soundly in their tents. The very night of the main raid Antigonus had returned in the early hours from across the river. He had found the girl who had been raped. She was dead; she had been mutilated. Antigonus left her there but returned with a Persian head. Two nights later he had gone south by boat and returned with another head, wrapped in a Persian cloak. The next night he had slipped out of the northern wicket gate down by the river and this time returned with two heads. Finally, last night he had gone across the river again and brought back yet another grisly bundle. In a sense five casualties meant nothing in a horde probably 50,000 strong. Yet morning after morning the news of finding yet another inexplicably decapitated corpse in yet another place was bound to summon up the very worst fears in the Persian army: a traitor turning his hand against his friends or, worse, far worse, a daemon able to strike at will throughout the sleeping camp.

Ballista was pleased with his new standard-bearer. He took little pleasure in the ghastly trophies, but he solemnly unwrapped each one, solemnly thanked its bringer. Each one was a mark of revenge for both Romulus and the unknown girl. Antigonus had a gift for this sort of thing. Ballista was glad they were on the same side.

Beyond Antigonus's nocturnal forays, beyond the normal activity of the besieged, the main activity of the seven days had been the construction of three huge mobile cranes. Every carpenter in the town had been seconded to work on them; likewise, every blacksmith had been forging the giant chains and implements they would deploy. With their completion, Ballista had the last major items necessary for when the Sassanids attempted to storm the town. Looking up and down the wall, the air already shimmering with heat where the large metal cauldrons hung over their fires, Ballista felt that he had done his best. He was far from sure that it was good enough, but he had done his best.

The sun was rising over Mesopotamia. A wash of gold splashed over the bright Sassanid banners, picked out their gorgeous costumes, the jewels in the headdresses. As one, every man in the vast host sank to his knees then prostrated himself in the dust of the desert. Trumpets blared, drums boomed, and across the plain rolled chants of 'Maz-da, Maz-da' as they hailed the rising sun.

The sun had now risen clear of the horizon. The chanting stopped, and the Persian army got to its feet. They waited in silence.

High on the battlements of the Palmyrene Gate, Ballista also waited and watched. The twenty-first day of April, ten days before the kalends of May: it was the Parilia, the birthday of eternal Rome. From the right of the Sassanid army, preceded by the Drafsh-i-Kavyan, the great battle flag of the house of Sasan, came the now familiar figure clad in purple riding a white horse.

'Shah-an-Shah, Shah-an-Shah.' A new chant rolled across the plain.

Shapur halted in front of the centre of the line. The great jewel-encrusted banner moved above his head, catching the sunlight, flashing yellow, violet, red. His horse stamped its foot, tossed its head and neighed, high and clear across the plain.

On the battlement Bagoas gave a small whimper of pleasure. 'The sure sign. When the charger of the King of King's does thus before the walls of a town, that place will surely fall.'

'Silence, boy.' Ballista would not have his slave spreading despondency. 'It is an easy enough omen to create.'

'What are they doing now?' Maximus asked. A line of seven roped men were being driven towards the priests, magi, around the Drafsh-i-Kavyan. 'This does not look good.'

Bagoas said nothing. He cast his eyes down. For once he looked rather shamefaced.

The men were wearing Roman uniforms. They were struggling, but being beaten forward. One fell. He was kicked back to his feet. They were driven to where a small fire was burning. A pot was hanging on a tripod, heating over the fire. The Romans were forced to their knees and held tightly. Their heads were forced back. One of the magi unhooked the pot from the tripod, lifted it free of the fire.

'Gods below, the barbarian bastards.' Maximus looked away.

The priest stepped over to the first of the prisoners. Two magi held the man's head. The priest tipped the pot. The man screamed.

'What is it?' Ballista tried to keep his voice level. 'What are they doing to them?'

'Olive oil.' Bagoas answered very quietly. 'They are blinding them with boiling olive oil.'

A single trumpet call was picked up by innumerable others. The vast Sassanid horde stirred itself and began to form up for its slow advance.

Gangs of men began to push the ballistae, mounted on squat carts or moved on rollers forward, to within effective range, about 200 paces of the walls. From there the stone-throwers would aim to destroy the defenders' artillery and knock down the battlements while the bolt-throwers swept Roman soldiers from the wall walks.

The mantlets were pushed to the fore. These would travel to within effective bow shot, about fifty paces from the town. Forming an unbroken line of reinforced wood, the mantlets were intended to shield both the Persian archers and the storming parties as they assembled.

Most ponderously of all, hauled by hundreds of men each, the three City Takers began to inch forward. These monstrous wheeled siege towers were made of wood but entirely clad in plates of metal and damp skins. Water was frequently poured down their sides from the top to try to prevent the enemy setting fire to them. They had ballistae on their upper levels, but these were only secondary to their main purpose. The City Takers were designed to creep up to and overtop the walls of the town, let down a drawbridge and release on to the battlements a mass of screaming warriors. As the drawbridges came down, a host of storming parties carrying ladders would burst forth in support from the line of mantlets.

Ballista looked at them. They were the key to the assault. Everything else would revolve around them. They were quite far apart. One was on the road, heading straight for the gate where Ballista stood. The others were aimed to hit the wall beyond, three towers away north and south. Travelling at about one mile an hour, in theory they could strike the wall in about half an hour. Ballista knew that was not going to happen. The City Takers would make many stops, to change the crews of men hauling them, to test, smooth and reinforce the ground ahead, as well as to fill in Ballista's traps – if, of course, the latter were detected.

Ballista judged that the assault would probably not come until midday. Unfortunately, that would be good for the attackers in several ways. The morning sun would no longer be directly in their eyes as it was now. It would give plenty of time for the City Takers to reach the walls and for subsidiary attacks to be ready to go in on the other walls.

Clouds of horsemen had been spotted the day before on the other sides of the northern and southern ravines. Ballista had altered his order of battle, ordering 300 men, 100 mercenaries from each of the numeri of the caravan protectors, to join the defence of the dangerously undermanned north wall. It was odd that this weakness had been spotted by his accensus, the completely unmilitary Demetrius, not by himself nor any of his army officers. Sometimes one got too close to things. As Ballista's people said: you could not see the wood for the trees.

Midday. The northerner turned the timing over in his mind. Midday. The time when Romans ate their first substantial meal of the day. Bagoas had told him that Persians ate later, towards late afternoon. At midday the Persians would not be hungry, but the Romans would. Ballista was about to issue orders to bring forward the time of the soldiers' lunch when he saw something that might prove to be terribly important.

The distinctive figure clad in purple riding a white horse was on the move. Although now accompanied by a glittering entourage of the high nobility and client kings, there was no mistaking the high, domed golden helmet, the long purple and white streamers that indicated the King of Kings.

Ballista had been waiting for this moment, had been praying that it would come. In the Roman army, at the start of a siege it was customary for the commander to ride forward into range of the defenders' artillery. It was a tradition that served two goals. At a purely pragmatic level, it gave the commander a fine chance to observe the state of the defences. At an altogether more intangible but possibly far more significant level, it allowed the general to rouse the spirits of his troops by demonstrating his studied contempt for the weapons of their enemies. A fine tradition, one which killed two birds with one stone. The only problem was that it sometimes killed the besieging general as well.

Until this moment Ballista had not known if the Sassanids held to a similar practice. Asking Bagoas had produced no useful answer – 'Of course, Shapur, the beloved of Mazda, has no fear of the weapons of his foes.' More and more the northerner wondered just how much or how little the Persian boy knew about war. Bagoas clearly came from the Persian elite, but was it becoming ever more likely that he was from a family of scribes or priests than one of warriors?

Shapur and his men reined in just outside artillery range. Animated conversation could be seen. The King of Kings was doing most of the talking. Informing his high-status audience of his view of the direction the assault should take, Shapur made wide arcs and sweeps with his arms, the streamers flying behind him.

Ballista stared intently not at Shapur but at two distinctive humps of stone left on either side of the road. The sides facing the wall were painted white. They marked 400 paces, the maximum range of his artillery. Come on, you cowardly eastern bastard. Come on, just have the balls to get within range.

Forcing his mind away, Ballista issued orders for the men to take their lunch no less than two hours earlier than usual. As the messengers moved away, the northerner realized with a nasty lurch that he had not issued the far more pressing orders for every piece of artillery to aim at the Persian king but not to shoot until the Dux Ripae gave the command. As the next batch of messengers moved away, Ballista was slightly reassured by the thought that their message most likely was redundant – it would be a very poor ballistarius indeed who had not already trained the weapon on the man on the white horse.

The trick of turning the washers, slackening the torsion and decreasing the apparent range of the weapons was an old trick, an obvious one. Had it worked? And even if it had, would the traitor have betrayed it? Was the Sassanid mocking him?

Shapur kicked on, and the white horse moved down the road towards the Palmyrene Gate. Past the whitewashed piles of stone, with his meteor trail of the powerful, Shapur came on. Allfather, Deceitful One, Death-Bringer, deliver this man to me.

Ballista was painfully aware of the expectation surrounding him. The dead silence on the battlements was broken only by the small noises of well-oiled machinery being subtly adjusted as the ballistae tracked their target. Wait until he stops moving. Do not snatch at this. Wait until the right moment.

Nearer and nearer came Shapur; closer and closer to the white-painted section of wall at 200 paces.

He stopped.

Ballista spoke.

Antigonus hoisted the looked-for red flag.

Twang – slide – thump: the great twenty-pounder by Ballista hurled its carefully rounded stone. A moment later it was joined by its twin on the gatehouse roof. Then, twang – slide – thump, twang – slide – thump: all the artillery along the western battlements joined in. For a couple of seconds the northerner admired the geometry of it all – the fixed line of the wall, the moving triangle of missiles all converging on the fixed point of the man on the white horse.

The rider in fur next to Shapur was plucked from his horse. Arms wide, the empty sleeves of his coat flapping, the man looked like a large six-limbed insect as the bolt threw him backwards. Towards the rear of the entourage two, maybe three horses and riders went down as a stone reduced them to a bloody shambles.

After the strike there was a shocked near-silence. Only muted sounds could be heard: the click of ratchets, the groan of wood and sinew under gathering pressure, and the grunting of men working frantically. The near-peace was broken by a rising roar of outrage from the horror-struck Sassanid horde.

Shapur took both sides by surprise. Putting spurs to his mount, he kicked it into a gallop straight ahead. Thundering towards the Palmyrene Gate, he pulled his bow from its case, took an arrow from his quiver and notched it. About 150 paces from the gate he skidded to a halt, drew and released the arrow.

Ballista watched its flight. With a superstitious dread he felt that it was coming straight for him. As they always do, it seemed to gain pace as it grew nearer. It fell just short and to the right of the northerner, clattering off the stone of the wall.

Shapur's mouth was moving. He was yelling his outrage, his anger, but the words could not be made out on the wall. Two horsemen drew up on either side of the king. They were shouting. One went so far as to try to grab his reins. Shapur used his bow as a whip to knock the hands aside. The white horse was spun around and, with a shake of his fist, the King of Kings was racing back towards safety.

Twang – slide – thump: the artillery pieces started to speak again. At this distance, against a fast-moving target, Ballista knew there was next to no chance of a projectile finding its mark.

Back in safety, Shapur could be seen riding along the front of the line haranguing his men. They began to chant: 'Sha-pur, Sha-pur.' Along the walls of Arete spread a counter chant: 'Ball-is-ta, Ball-is-ta.'

The Dux Ripae took off his helmet. The south wind caught his long fair hair and blew it out behind him. He waved to his men. 'Ball-is-ta, Ball-is-ta.'

'So, who was it we just killed?' He spoke conversationally.

'Prince Hamazasp the son of Hamazasp the King of Georgia.' Strong but hard-to-read emotions played across Bagoas's face. 'If his spirit is not avenged it will forever more be a stain on the honour of the King of Kings. Now there can be no quarter.'

With a child-like spontaneity Ballista threw his helmet in the air and caught it. 'That should concentrate the boys' minds.' Laughing, he turned to the soldiers on the gatehouse. 'I don't know about you, but I don't fancy letting those magi get their hands on me.' The men laughed in turn. By nightfall, the exchange, often altered and embellished, would have reached every corner of the city.

'How long until their line comes into extreme artillery range?'

'At least a quarter of an hour, maybe more.' As was only right, Mamurra, the praefectus fabrum, the man who was meant to know siege machinery, answered his Dux.

'Then, Calgacus, can you find us some food? Trying to kill the despot of half the known world has made me very hungry.'

Demetrius watched his kyrios eating bread and cold pheasant, talking and joking with the other men: Mamurra, Turpio, Maximus, Antigonus, the crews of the artillery pieces. They were passing a jug from hand to hand. The young Greek had never admired Ballista more. Did the kyrios plan these things or did they just come to him in a divinely inspired flash? Did he always know what he was doing? However it was, it made no difference: it was an act of genius. The hideous actions of the magi, the death of the Georgian prince and the exchange with Bagoas came together to tell a story that anyone could follow. By nightfall every soldier in Arete would be stiffened by the knowledge of what would happen to him if he fell into the hands of the Sassanids: capitulation meant torture and death; better to die on one's feet, weapon in hand.

Soon enough the Persians drew near the line of signs that marked 400 paces from the wall, maximum artillery range. The Dux Ripae had repeatedly stressed the need for these range markers, and those at 200 paces, to be inconspicuous. They were to be visible to the artillerymen but not to attract the attention of the besiegers. The majority of artillery crews had gone for carefully arranged, hopefully natural-looking low humps of dun-coloured rocks. There was not an artilleryman in the town who had not laughed, although only surreptitiously – never when the big man or his vicious-looking bodyguard were around – at the markers opposite the Palmyrene Gate chosen by the Dux himself: 'well, brother, that is a northern barbarian's idea of inconspicuous: two bloody great piles of stone followed by a bloody great wall, the whole lot painted white.'

The Persians were advancing sensibly, coming on in good order. The main body was advancing at the speed at which the ballistae could be moved. The mantlets, which could be transported considerably faster, were staying with the artillery to try to shield them. The three great siege towers were lagging quite some distance behind.

Ballista's eyes were concentrated on the two white stones 400 paces away. He held a piece of bread and cheese in one hand and a jug in the other, both completely unconsidered. When the Persians passed the stones, they would have to advance for 200 paces into the teeth of the artillery on the town wall. Hauling their artillery forward, for those 200 paces the Sassanids would be unable to hit back. The northerner had ordered his artillery to concentrate exclusively on the enemy ballistae and the men moving them. Initially, little could be expected – the range was too great for any accuracy – but things should improve as the slow-moving targets came closer. Knock out as many of them as we can before they can get at us. With luck, the stone-throwers would wreck some enemy engines. The bolt-throwers could not damage the ballistae themselves, but they could kill and alarm the men moving them and this would slow down their progress, keep them longer unable to strike back, longer exposed to the stone-throwers on the town wall.

Ballista nodded to Antigonus. The standard-bearer raised the red flag. Twang – slide – thump, twang – slide – thump: up and down the wall the artillery opened up.

The first volley achieved nothing and after a couple of minutes there was no semblance of volley shooting. The crews of the artillery pieces worked at different speeds. Ballista was far from convinced that the quickest were necessarily the best – better to take a little extra time and aim well. It cost him some effort not to take over the laying of the big twenty-pounder next to him. The northerner went to scratch his nose, found a jug in one hand, food in the other. He drank and ate.

Cheers, loud cheers, from the wall off to the right. Ballista looked just in time to see a wheel spinning in the air like a tossed coin. A cloud of dust rose from the plain. Small, brightly clad figures staggered out of it. One of the stone-throwers towards the north of the wall had scored a direct hit. One Sassanid ballista down, nineteen to go.

More cheers, this time off to the left. Ballista could not see the cause. Maximus pointed. 'There! There! Gods below, that's fucked him.' Ballista followed the direction of the Hibernian's outstretched arm. Way, way out from the wall, way out behind the main body of the Persians, was the southernmost of the three siege towers. The great Sassanid City Taker was leaning drunkenly forward, its front wheels deep in the ground.

'Tyche,' said Mamurra. 'I do not think that we dug any pits that far out. Its weight must have made it go through into one of the very furthest out of the old underground tombs. Anyway, they will not get that brute out again today.'

Any battle, like anything in nature, goes in phases. Now for a time the tide was with the defenders, and good news flowed in. As Ballista finished his bread and cheese two messengers treading on each other's heels ran up the steps to the top of the gatehouse.

While the first spoke Ballista passed the jug from his own hand to the other waiting messenger.

The Sassanid attack on the north wall had come to nothing. A great mass of men – it was reckoned there were about 5,000 of them – had been drawing up on the plateau north of the ravine. They were still a very long way off, at the very limits of artillery range, when Centurion Pudens ordered the bolt-thrower on the postern tower to try a shot at them. The ballistarius, more in hope than expectation, had aimed at the leading rider, a richly clad man on a gloriously caparisoned horse. The bolt had taken the Sassanid off the horse easy as could be, left him pinned to the ground. Their leader dead, the reptiles had swarmed away.

Ballista thanked the messenger, and gave him some coins. The other handed the jug over to his colleague and told his news.

The Persians, from somewhere, had got together five boats and crammed about 200 men into them. Stupidly, they had followed the western bank of the river down to Arete. As soon as the boats came into range of the bolt-throwers on the two north-eastern towers, the boatmen, local men who had been pressed into service, dived over the sides, swam to shore and deserted. From then on the boats were in utter confusion. They were little better than drifting while being shot at from the elevation of the walls by bolt-throwers and bowmen. When eventually they tried to land near the fish market, they were easy targets for at least ten artillery pieces and no fewer than 500 archers from the numerus of Anamu. Three of the boats capsized; one foundered just short of the nearest island in the Euphrates; one drifted away downriver. Most of those not killed by missiles were drowned. Only about twenty seemed to have escaped downriver, and another twenty or so were stuck on the island.

As the tale ended, with the Sassanids on the island, Antigonus looked enquiringly at Ballista, who enigmatically said yes, adding, if they were all still around that night. The northerner thanked the messenger and again parted with some coins.

But the tide cannot flow one way for ever. All too soon, and at the cost of only one more ballista, the Sassanid artillery had crossed their zone of impotence. They had reached their intended shooting positions just within effective range. Persians swarmed about, dismounting the artillery from their rollers, setting up protective screens, putting the ammunition to hand, winching back the sliders, placing the missiles, aiming and releasing.

Ballista felt a slight tremor run through the gatehouse as a stone struck. The time of carefree observation was over. Now the air had become a thing of menace; everywhere the tearing, ripping noises of missiles. To the right a man screamed as a bolt shot him from the wall walk. To the left a short section of battlements exploded in stone splinters as a missile struck. A man lay in the middle of the debris moaning. Another lay silent. Passing the word for carpenters to erect a makeshift battlement, Ballista reflected that, other things being equal, the defenders should win this exchange of artillery. They had twenty-five ballistae to eighteen, and the advantages of a higher position, as well as stone, not wooden, walls for protection.

Yet other things were not equal. The two City Takers remaining mobile had crept forward into maximum artillery range. Just when the enemy would be shooting back, the northerner was going to have to order his ballistarii to change targets. As they came in range, the huge siege towers would be the sole targets. Now it would be the turn of the defending artillerymen to endure shot without being able to return it; there can be little worse for any soldier. About to send off the runners to give the order, Ballista added that any ballistarius who aimed at anything other than one of the siege towers once they were within range would be flogged to death. Allfather, the exercise of power has corrupted my soul.

Leaving their ballistae 200 paces from the wall, the main body of Persians huddled as close as possible behind the line of mobile shields. Men fell to traps underfoot and arrows slicing down from above. Yet to the defenders it seemed no time at all before the line of mantlets was established a mere fifty paces from the walls and the Persian bowmen were bending their bows. Ten, twenty, thirty thousand arrows; it was impossible to guess. Like a shadow passing over the face of the sun, they made the day grow darker.

All along the wall, and behind it, the arrows fell as thick as hail in the deep midwinter. On the wall, and in the streets and alleys behind, men fell. The archers on the wall shot back. The defenders had some advantages: they were higher up, well protected by stone crenellations and the stout shields of the legionaries; almost all their arrows found their mark – so vast was the number of Sassanids that they formed a dense target and the mantlets could not shelter them all. But it was an unequal contest: fewer than 650 bowmen against innumerable thousands.

Sassanid arrows were striking home. Defenders were falling – far too many. Ballista wondered if all his planning, his clever ruses, would prove in vain. Would sheer numbers prevail? Would sheer weight of missiles clear the walls and leave the city open?

Endurance. They just had to endure. Ballista knew that only discipline, old-fashioned Roman disciplina, could get them through. For nine nights and nine days the Allfather had hung on the tree of life. His side pierced by a spear, voluntarily the Allfather had endured on the tree to learn the secrets of the dead. The northerner smiled. So much for the romanitas of the Dux Ripae.

The white draco hissing in the breeze attracted the full ferocity of the Sassanids. The air above the Palmyrene Gate was thick with missiles. Ballista was hunkered down behind the parapets in the midst of a makeshift shieldwall. It was hard to see or hear. Then, above the awful clamour of the storm of steel and stone rose the sound of cheering. Thin, half-swamped by the noise of battle, but exultant, came chanting: 'Ro-ma! Ro-ma!'

Ballista peeked out around the crenellations. He jerked his head back into safety as an arrow snickered off the wall. He looked again. The northern half of the plain was enveloped in a great mushroom cloud of dust. Not wanting to tempt fate, Ballista retreated behind the parapet for a few moments. When he looked again the dust had cleared a little. He could see why his men were exulting. The northernmost City Taker was no more. In its place was a tortured tall frame of beams and girders. As Ballista watched, a man leapt from the top storey. The falling man, incongruously, looked as elegant as a pantomime dancer. Two, three, four more eastern men jumped to a certain death. Then, with a ponderous inevitability, the remains of the tower imploded.

A strange hush settled across the battlefield. The fighting slackened as both sides came to terms with the enormity of what had happened. The siege tower had been heading almost directly towards a tower housing one of the biggest pieces of artillery. The repeated impact of twenty-pound stones slamming in at a great pace must literally have shaken the City Taker apart.

Demetrius looked around. The fighting top of the Palmyrene Gate was littered, almost carpeted with spent missiles. As the fighting died down, defenders slumped down against the walls or the two enormous ballistae. Although he tried not to, the young Greek could not help repeatedly looking at the two corpses thrown in the corner. A slick pool of their mingled blood seeped out from under them. Demetrius both wanted and at the same time did not want to know their identity.

Was the fighting over? Zeus, Apollo, Athena and Artemis, please let it all be over, at least for today. Demetrius noticed some slaves carrying parcels and jars emerge from the trapdoor. They bent double as they moved. Stray missiles were still flying across the roof. For a moment the young Greek had no idea what the slaves were doing. Then, looking at the sky, he realized that it must already be towards the end of the fourth hour of daylight, the time that the kyrios had ordered the troops to take their early lunch. In one way the time had gone so quickly; in another, the screaming and the terror seemed to have lasted for days. Demetrius thought how Zeus, in the divine poetry of Homer, held back the day so that Odysseus and Penelope could enjoy their lovemaking and sleep. Today was nothing like that; Arete was nothing like Ithaka.

Earlier, when Ballista had called for his impromptu mid-morning snack, Demetrius had been unable to eat; there had been no saliva in his mouth. Now, as the fighting seemed to be dying down, he felt ravenous. Taking some bread, cheese and an onion, he started to wolf them down.

The kyrios was chewing in a desultory way. He was sitting on the floor with his back against the southern wall, Maximus and Antigonus either side of him. In quiet voices they were holding an intermittent technical discussion on the limits of depression of artillery pieces. Demetrius wondered at them. How could repetition ever so dull a man's senses that this morning of horror, this dealing in death, could become as mundane as reaping a cornfield? He began to giggle. Maybe it was because they were barbarians; an Angle, a Hibernian and a Batavian. To stop his giggling, Demetrius bit a large mouthful out of his onion.

Arete was in the eye of the storm. This isolated and previously insignificant town had been willed by the gods to become the latest focus of the eternal war between east and west. The conflict had always been there, from the earliest records. First, the eastern Phoenicians had kidnapped Io and the Greeks had responded by abducting first Europa then Medea. After the Trojans had taken Helen, things moved from girl-taking to war-making. The Achaeans burnt Troy, the Persians burnt Athens, and Alexander burnt Persepolis. The sands of the desert were sodden red with the wreck of Crassus's legions at Carrhae. Abandoned Roman corpses marked Mark Antony's retreat from Media. Julius Caesar was struck down on the eve of yet another war of revenge. Wars of revenge had repeatedly been undertaken by the emperors Trajan, Lucius Verus and Septimius Severus. Then came the Sassanids, and the east had struck back. Thousands of Roman dead at Meshike and Barbalissos. Antioch, the metropolis of Syria, and so many others burning in the time of troubles. East against west, the conflict that could never end.

Arete was the epicentre of a conflict of cosmic proportions; a never-ending clash of civilizations, an eternal clash of gods. The full might of the east was hurled against the west, and here eternal Rome – humanitas itself as some would have it, all of its arts and philosophy – was defended by three barbarians eating bread and cheese. Demetrius's stream of consciousness was broken by the sudden arrival of a soldier.

The messenger also trampled into Maximus's excellent reverie. The Hibernian had lost interest in the finer points of depressing artillery some time ago. His mind was running over the new girl at The Krater: nipples like a blind cobbler's thumbs, trim little delta, willing as you like. It was funny with girls – no matter what sort of nipples they had, they always wanted different ones. The girl from The Krater with her big brown aureoles like dinner plates said she would rather have small, neat little nipples. The girl from the bar at the north end of town, who had tiny, delicate pink nipples, wished hers were bigger. Maximus did not care; the girls were both lively well-built blondes. Certainly they would look good together.

The messenger was attempting to salute while bent double. Ballista and Antigonus saluted back without getting up. As a slave rather than a soldier, Maximus took pleasure in not feeling the need to join in.

'Good news, Dominus.' The soldier sat down with relief when Ballista indicated. 'The barbarian attack on the south wall has been driven off. There were about 5,000 of them. The reptiles formed up out of range on the plateau. But by the time they were descending into the ravine we had ten ballistae on them. The bastards were looking shaken when they started to climb our side of the ravine. When the bowmen of larhai and Ogelos started shooting and we rolled those bloody great stones you had us put out down among them the Sassanids ran like the true easterners they are – no stomach for it, no balls.'

Living in the moment, almost like a child, Maximus had actually forgotten all about the threat to the southern wall. But the news was welcome: things on the desert wall were bad enough on their own.

Ballista thanked the messenger and sent him back with an order for Iarhai to bring 300 of his archers round on to the desert wall.

Trumpets rang and drums boomed across the plain. Sassanid commanders shouted themselves hoarse trying to put the enthusiasm back into their men, to lift the tempo of the attack. The stream of incoming missiles picked up. Demetrius cowered closer to the floor. Wearily, Ballista, Maximus and Antigonus got to their feet and huddled behind the parapets, now and then looking out.

A terrible crash came from the tower to the north of the gate. Again a cloud of ominous dun-coloured dust billowed into the sky. It was followed by a rhythmic shout of pain like an animal bellowing. A Sassanid stone-thrower had scored a direct hit on one of the two Roman ballistae on the tower; the resulting jagged, fast-flying splinters of wood had reduced the platform of the tower to a charnelhouse.

Before Ballista could issue any orders, Mamurra had appeared on the stricken tower. The praefectus fabrum was organizing a work gang to throw the shattered remains of the bolt-thrower off the tower and sending men to drag a spare piece of artillery from the magazine. The corpses joined the remnants of the machine on the ground and the living were pushed into getting the remaining ballista working.

For the moment the defenders' main problem lay in the one Sassanid City Taker remaining operative. It had resumed its painful advance on the Palmyrene Gate. While it stood and was capable of movement, all the artillery of the defenders that could get an aim on it had no other choice. Only the towers at the extreme north of the desert wall were able to hit back at the Sassanid artillery tormenting them.

The last City Taker was taking a dreadful pounding. Again and again smooth round artillery stones, six-pounders and twenty-pounders, smashed at terrible speed into the tower. Bolts from ballistae and arrows caused havoc among the myriad men hauling the behemoth. The City Taker shook, seemed to stagger, but then, with new men on the ropes and with the terrible squealing of thousands of joints of wood under intense pressure, it advanced again.

Twice, work crews raced ahead of the siege tower to deal with Ballista's traps. The carefully concealed pits at one hundred and at fifty paces from the gate were filled in, but at frightful cost. The crews ran into an almost solid wall of tipped steel. The pits were partly filled with their bodies.

Inexorably the City Taker rolled on. If it reached the gate, if its drawbridge crashed down on the roof of the gatehouse, the siege was over, the town would fall. Ballista knew that now there was just one hope of stopping the siege engine reaching the gate. Did the Persians know that there was one more pit hidden a mere twenty paces from the gate? The Suren had not come that close. As far as Ballista knew, no Persian had come that close. But had the traitor warned them?

Nearer and nearer came the skin-clad tower. The smell of uncured hides, wood and the sweat of men preceded it to the gatehouse. Thirty paces, twenty-five: no work crew racing ahead. Twenty paces. Nothing. Had Ballista miscalculated? Were the beams too strong? Would the City Taker cross unhindered over the trap?

There was a deep, deep groan. The surface of the road moved, the hidden boards over the pit began to buckle under the weight of the tower. A distinctive smell wafted up. One by one the boards snapped. The tower lurched forward. Men screamed.

Ballista snatched up a bow and arrow. The smell of pitch was strong in his nostrils. He touched the combustible material to a brazier. The arrowhead flared. Taking a deep breath, he stepped out from the shelter of the crenellations. He flinched as a Persian arrow shot past his face. He exhaled, and forced himself to lean out over the wall, to ignore the dangers, to concentrate on what had to be done. Dimly he was aware of missiles nicking off the stone around him. There was the dark opening of the trap. He filled his lungs, drew the bow and released. The arrow seemed to accelerate away, a smoke trail curling after it.

Other fire arrows darted into the pit, into the mouth of the large terracotta storage jar which had been hidden there. With a roar the naptha ignited. The flames shot up, curling and licking around the siege tower, darting up its companionways and the ladders inside. Men screamed. Ballista smelt something like roast pork.

'Ball-is-ta, Ball-is-ta.' The chants rang out from the walls. 'Ball-is-ta, Ball-is-ta.'

But the ordeal of the town of Arete was not yet over for the day. The sight of their tower and their men burning goaded the Sassanids. Trumpets called and drums thundered. Noblemen roared commands.

'Per-oz, Per-oz, Victory, Victory.' A proud chant came from the desert. 'Per-oz, Per-oz.'

Like a great wave driven against the shore by the frenzy of the sea, the easterners came out from behind their line of mantlets and set on towards the wall. The storming party was several thousand strong, each man clad in armour. The Sassanid knights, the clibanarii, had dismounted. The noblemen were even carrying their own siege ladders.

The human wave had fifty paces to cross, fifty, long, long paces. From the first step men fell, smashed backwards by the bolt from a ballista, curling round the shaft of an arrow, clutching a foot lacerated by a caltrop, screaming piteously as the stake concealed in its pit penetrated soft tissue, scraped down bone. Men fell in droves – as they crossed the open space, as they descended into the ditch, as they climbed out again. The Sassanids left lines of their dead and dying, but they reached the earth bank against the wall of Arete, they swung the siege ladders up against the battlements, and the first of them began to climb.

Now the simple but vicious devices honed by generation after generation of wicked, heartless human ingenuity were unleashed against the Sassanids. As the ladders banged against the wall defenders sprang forward with rustic pitchforks. Catching the uprights between the tines, the soldiers pushed the ladders sideways. Despite the arrows whistling past their ears, more defenders joined in; pushing, pushing ever harder. As one man fell another took his place. Those siege ladders not well secured at the base slid sideways, gathering momentum, shedding men, some crashing into neighbouring ladders. Sassanid warriors went spinning head over heels down to the unforgiving ground.

Great rocks, barely to be lifted by three or four men, were manhandled on to the parapet. They teetered for a second then tipped. Brushing men off the ladders, smashing the rungs, pushing the uprights irreparably apart, the stones plummeted to earth.

High out over the battlements soared the arms of Ballista's three new giant cranes. Levers were pulled and the great chains released their immense boulders. Where they struck, in the blink of an eye ladders became kindling, men were reduced to a pulp.

All along the wall walk were flurries of activity. Teams of four legionaries thrust well-wrapped metal poles through the handles of the big metal cauldrons hung over the fires. With haste, but carefully, they lifted the glowing bowls clear of the intense heat. Delicately they manoeuvred their spitting, crackling burdens to the edge. Grunting with effort, they hoisted the poles on to their shoulders then, most dangerous of all, they carefully, so very carefully, tipped the contents over the parapet.

Men screamed. The white-hot sand flowed down the face of the wall, down the earth bank. The sand set fire to hair and clothes. The tiny grains penetrated the gaps in armour, the eye sockets in helmets, burning and blinding. Men ran, screaming, ripping off their armour, which had turned traitor, trapping the agonizing, scalding sand. Men rolled on the ground, beat at themselves, all unconscious of the arrows of the defenders, which continued to rain down.

The carnage below the walls was immense. Yet not all the Sassanid ladders were pushed aside or shattered. Still, gaily clad warriors, silk surcoats and streamers floating around steel armour, climbed unbroken ladders. There was no chanting now. They were saving their breath for climbing, for what was waiting for them at the top.

It is hard to climb a ladder and fight at the same time. For most of those Sassanids who reached the top all that awaited them was a series of blows from a Roman spatha which sent them crashing back down again. But in a few places warriors made it over the parapet and on to the battlements. Most of these footholds were overrun almost immediately, swamped while the numbers still overwhelmingly favoured the defenders.

'Look, Kyrios, over there.' Demetrius pointed to the wall walk just south of the gatehouse. A knot of four Sassanid clibanarii had made it over the crenellations. They stood, shoulder to shoulder, their backs to the ladder. Five or six bodies, Persian and Roman, lay at their feet. A ring of defenders had drawn slightly back from them. As the Greek youth watched, another eastern warrior scrambled over the parapet, then another.

'With me. Maximus, Antigonus, equites singulares, with me.' Without waiting to see if his order was being obeyed, Ballista drew his spatha and hurled himself through the trapdoor and down the stairs.

As the press of men on the roof thinned out Demetrius dithered. He drew his sword. Should he follow his kyrios? He felt foolish holding the gladius that Maximus had given him. If he went down there he would just get himself killed, would get in the way and get the others killed.

Demetrius saw his kyrios emerge from the tower on to the wall walk below. The northerner set off at a run. With his left hand he – unbuckled and tossed aside his black cloak. It fluttered and rolled down the inner earth ramp. Maximus and Antigonus were with him, six equites singulares right behind. The Dux Ripae was yelling some war cry in his native tongue.

There were eight Sassanids in the group by the time Ballista reached them. The nearest one swung overhand at the northerner's head. Ballista brought his sword across his body, rolling his wrist, forcing the blade of his opponent outward then, seemingly in the one motion, launched a backhanded cut which landed heavily in the Persian's face. As the first Sassanid fell sideways Ballista aimed a series of heavy blows at the next man, who covered up and cowered behind his shield.

Demetrius watched, heart in mouth; so much going on at once. Maximus killed a Persian. Then Antigonus another. One of the equites singulares went down. More Sassanids were falling than Romans. More Sassanids were falling than were getting off the ladder and on to the battlements. A group of Iarhai's mercenaries was attacking from the far side. Ballista unleashed a barrage of savage cuts which drove an easterner to his knees, battered his shield aside, thrust the spatha sickeningly into his face. As the kyrios put his boot on the man's chest to pull his sword out he half slipped. The walkway was slick with blood. A Sassanid seized the opportunity to lunge forward, catching Ballista's helmet a glancing blow. With his left hand the northerner swept off the damaged helmet. With his right he parried the next blow. One of Iarhai's mercenaries drove a sword into the Persian's back.

It was done. As if at a signal the three Sassanids still standing turned and scrambled for the elusive safety of the ladder. All three were cut down from behind.

Ballista rubbed the sweat from his eyes. He looked up and down the wall. There were no easterners still on the wall walk. Still taking care, crouching behind the battered crenellations, he looked over the wall. It was done. Panic was spreading through the Sassanid ranks. Where before individuals, the wounded, real or pretend, had been making their way back to the camp, now there were small groups. As Ballista watched, whole bodies of warriors turned and fled. The trickle had become a flood. Shapur's assault had failed.

'Ball-is-ta, Ball-is-ta.' The chants rang across the plain, taunting the retreating Sassanids. 'Ball-is-ta, Ball-is-ta.' Some of the legionaries howled like wolves, the story of the Dux's father Isangrim turning from something to mock into a source of strange pride.

Ballista waved to his men, shook hands with or hugged those around him. As he was released from Maximus's bear hug, the northerner recognized the leader of the group of Iarhai's mercenaries.

'What the fuck are you doing here?' His voice was harsh. His concern for her was making him angry.

'My father was… indisposed. So I brought the men you asked for.' Bathshiba met his gaze. One of her sleeves was torn, a smear of blood showing.

'Allfather, but this is no place for a girl.'

'You did not object to my help just now.' She stared up at him defiantly.

'That was you?'

'Yes, that was me.'

Ballista mastered his anger. 'Then I must thank you.'