The Byzantine Empire was at war with the Sassanids from 507, supposedly because Kavadh I had tried to force the Iberians to become Zoroastrians. The Iberian king fled from Kavadh, but Kavadh tried to make peace with the Byzantines, and attempted to have Justin I adopt his son Khosrau. Justin and his nephew and heir, Justinian I, refused and sent his generals Sittas and Belisarius into Persia, where they were initially defeated. Justinian tried to negotiate but Kavadh instead sent 40,000 men towards Dara in 529. Belisarius was sent back to the region with Hermogenes as his co-commander and 25,000 men in 530; Kavadh replied with another 10,000 troops under the general Perozes, who set up camp about five kilometers away at Ammodius.