Parthia, an ancient country corresponding to Northern Persia; was inhabited by a people of Scythian origin, who adopted the Aryan speech and manners, and subsequently yielded much to Greek influence; after being tributary successively to Assyria, Media, Persia, Alexander the Great, and Syria, they set up an independent kingdom in 250 B.C. In two great contests with Rome they made the empire respect their prowess; between 53 and 36 B.C. they defeated Crassus in Mesopotamia, conquered Syria and Palestine, and inflicted disaster on Mark Antony in Armenia; the renewal of hostilities by Trajan in A.D. 115 brought more varied fortunes, but they extorted a tribute of 50,000,000 denarii from the Emperor Macrinus in 218. Ctesiphon was their capital; the Euphrates lay between them and Rome; they were over thrown by Ardashir of Persia in 224. The Parthians were famous horse-archers, and in retreat shot their arrows backwards often with deadly effect on a pursuing enemy.