Arsacid dynasty

Rulers of ancient Parthia c. 250 BC–AD 226, who took their titles from their founder Arsaces. At its peak the dynasty controlled a territory from eastern India to western Mesopotamia, with a summer capital at Ecbatana and a winter palace at Ctesiphon. Claiming descent from the Persian Achaemenids, but adopting Hellenistic Greek methods of administration, they successfully challenged Roman expansion, defeating the Roman general Crassus at the battle of Carrhae in 53 BC. The Arsacid dynasty came to an end with the overthrow of Parthia by Ardashir in AD 226; it was succeeded by the Sassanian Empire.

Two of the dynasty's greatest rulers were Mithridates II (302–265 BC), who conquered Cappadocian and Paphlagonian territory to form the nucleus of Pontus, and Phraates III (died 57 BC), the son of Sanatrucesi, who formed an alliance with the Roman general Pompey 66 BC.