The 5th to mid-3rd millennia
Rather less is known of the cultures in this time range in Iran than of contemporary cultures elsewhere in the ancient Middle East. Research has tended to concentrate on the Neolithic and protohistoric periods, and the scattered evidence for important cultural and artistic developments in the Chalcolithic Period (Copper Age) and Early Bronze Age resists coherent summary. It is clear that trends that began in the late Neolithic Period continued in the millennia that followed and that the rugged, broken landscape of the Iranian plateau forced people into a variety of relatively isolated cultures. In no instance, with the important exception of Elam (see The Elamites, below), did Iran participate in the developments that led to fully urban civilization in lowland Mesopotamia to the west or in the Indus valley to the east. Throughout prehistory the Iranian plateau remained at the economic and cultural level of village life achieved in the Neolithic Period. The separate cultural areas on the plateau are as yet barely understood by the modern archaeologist in any terms other than through the painted pottery assemblages found at several sites throughout Iran. Though they developed in comparative isolation, each of these areas does yield some evidence of cultural contact with its immediate neighbours and, in some striking cases, with developments in the centres of higher civilization in Mesopotamia. Trade would appear to be the principal mechanism by which such contacts were maintained, and often Elam appears to have acted as an intermediary between Sumer and Babylon on the one hand and the plateau cultures on the other. Trade across the northern part of the plateau, through the sites of Tepe Hissar and Sialk, most probably involved transshipping semiprecious stones such as lapis lazuli from Afghanistan to Mesopotamia. The appearance of proto-Elamite tablets in Sialk IV may bear witness to such trade. So also may the appearance of similar proto-Elamite tablets at Tepe Yahya south of Kermān and in the great central desert provide evidence of trade connections between Mesopotamia and the east—in this case a trade that may have centred on specific items such as steatite and copper. Parsa perhaps also participated in such trade networks, as is suggested by the appearance there, alongside strictly local ceramics, of wares that have clear Mesopotamian affinities. In the west-central Zagros, outside influences from both the north and the west can be traced in the ceramic record; such is also the case for local cultures in Azerbaijan to the northwest. In general, however, these millennia represent a major dark age in Iranian prehistory and warrant considerably more attention than they have received.