principality was wilderness and therefore res nullius. Kliuchevskii describes as follows the procedure by which ownership was asserted in appanage Russia other than by inheritance:
This land is mine, because it is my men who cultivate it, whom I have attached to it: such was the dialectical process by which the first Russian landowners assimilated the idea of private property in land. Such juridical dialectic was natural at a time when the prevailing method of acquiring landed property in Russia was the occupation of wild expanses belonging to no one.6 Unable to colonize the empty land by themselves, but eager to have it populated because colonists enriched the area and brought income, princes solicited well-to-do military men, monasteries and peasant families to come and settle down. In this manner there emerged in each appanage principality three principal types of land tenure: 1. the private domains of the prince directly exploited by him; 2. the estates of the landowners and monastic establishments; and, 3. the so-called 'black lands', cultivated by free peasants. Economically, the three types did not differ much from each other except in size. Appanage Russia knew no large latifundia. Even the biggest properties consisted of numerous tiny units - villages of one or two households, fisheries, apiaries, orchards, mills, mines - all scattered pell-mell along river banks and in isolated forest clearings.
The prince was the principality's largest landowner. The lion's share of his revenues came from the exploitation of his private domains; the prince's economic power rested on the oikos, his household properties. This was worked and administered by a labour force composed mostly and in some principalities almost exclusively of slaves, called kholopy. The slaves came from two principal sources. One was war; many kholopy were captives and descendants of captives taken in raids on neighbouring principalities, so common during the appanage period, or in forays into the forest wilderness. The other source was the poor who had been either forced into bondage because they could not pay their debts, or else entered into bondage voluntarily in search of aid and protection. Historical experience suggests that in the case of economies based on slave labour the decisive factor may often be the supply rather than the demand: i.e. that slave economies can come into being because of the availability of a massive supply of slaves for whom work must be found.* The rupture of trade with Byzantium, where slaves had been in great demand, created in Russia of the twelfth and thirteenth centuries a glut of human merchandise. There are recorded instances when, following successful military campaigns, five slaves were sold for the price * The slave economies of the Americas are an exception to this rule.