or Bactriana (now Bokhara), an ancient kingdom of Asia, bounded on the W. by Margiana, N. by the river Oxus, E. by Asiatic Scythia, and S. by the Pamirian range. This country was very fertile, and inhabited by a numerous and warlike race. It became a Persian province about the time of Cyrus, and afterwards figured in the wars of Alexander, being celebrated for its cavalry. It formed part of the kingdom of the Seleucidae; but about B.C. 256, Theodotus, who was the governor, threw off the Grecian yoke, and Bactria remained independent till about B.C. 126, when it was conquered by the Parthians. Its capital was Bactra or Zarissa, corresponding to the modern town of Balk. The history of Bactria began to be illustrated by Colonel Tod's discovery of Bactrian coins (Royal Asiatic Soc. Trans. 1824); since which time various travellers have completed the series, such as now found in the Parisian and London Museums. See BOKHARA, BALK.