BACTRIA, or BACTRIANA, an ancient kingdom of Asia, bounded on the west by Margiana, on the north by the river Oxus, on the south by Mount Paropamisus, and on the east by the Asiatic Scythia and the country of the Massagete. It was a large, fruitful, and well-peopled country, containing, according to Ammianus Marcellinus, a thousand cities, though of these only a few are particularly mentioned by historians, of which that formerly called Maracanda, now Samarcand, is the most considerable.