The opportunity was not long in presenting itself.

In A.D.481 Perozes suffered a defeat at the hand of the barbarous Koushans, who held at this time the low Caspian tract extending from Asterabad to Derbend.

Iberia at once revolted, slew its Zoroastrian king, Vazken, and placed a Christian, Vakhtang, upon the throne.

The Persian governor of Armenia, having received orders to quell the Iberian rebellion, marched with all the troops that he could muster into the northern province, and left the Armenians free to follow their own devices.

A rising immediately took place.