SOGDIANA (Sugdiane, O. Pers. Sughuda), a province of the Achaemenian Empire, the eighteenth in the list in the Behistun inscription of Darius (i. 16), corresponding to the modern districts of Samarkand and Bokhara; it lay north of Bactriana between the Oxus and the Jaxartes, and embraced the fertile valley of the Zerafshan (anc. Poly timetus) . Under the Greeks Sogdiana was united in one satrapy with Bactria, and subsequently it formed part of the Bactrian Greek kingdom till the Scythians (see SCYTHIA) occupied it in the middle of the 2nd century B.C. The valley of the Zerafshan about Samarkand retained even in the middle ages the name of the Soghd of Samarkand. Arabic geographers reckon it as one of the four fairest districts in the world.