Cyaxares (r.625–585 BC)

Cyaxares, son of Phraortes, founder of Median power, was one of the kings who brought about the fall of Nineveh (612 B.C.) and broke the hegemony of theAssyrians. The Persian ruler of about the same time, Cambyses I, was vassal to Cyaxares.

Cyaxares was the third king of Media, but only ruled after the Scythians had been driven out. Under Cyaxares the Scythians were overthrown. Cyaxares reorganized the military into special units, majoring upon particular armaments; spearmen, bowmen and cavalry. This reorganization made them rather a match for the Assyrian armies.

As king of Media, he helps Cyrus conquer Assyria. He later gives his daughter to Cyrus in marriage. There is some rivalry between Cyrus and Cyaxares, but in general they work in concert as friends and allies.  
Cyaxares (r.625–585 BC)