Phraates IV was King of Kings of the Parthian Empire from 37 to 2 BC. He was the son and successor of Orodes II, and was given the throne after the death of his brother Pacorus I. Phraates IV soon murdered all his brothers, and also possibly his father. His actions alienated the Armenians and also some of his nobles, including the distinguished Monaeses, who fled to the Roman triumvir Mark Antony, but shortly returned and reconciled with Phraates IV.

Orodes II, was King of Kings of the Parthian Empire from 57 BC to 37 BC. He was a son of Phraates III, whom he murdered in 57 BC, assisted by his elder brother Mithridates IV. The two brothers quickly fell out and entered into a dynastic struggle, in which Orodes was triumphant.