The Battle of Nineveh was the climactic battle of the Byzantine-Sassanid War of 602–628. In mid-September 627, Heraclius invaded Sasanian Mesopatamia in a surprising, risky winter campaign. Khosrow II appointed Rhahzadh as the commander of an army to confront him. Heraclius' Göktürk allies quickly deserted, while Rhahzadh's reinforcements did not arrive in time. In the ensuing battle, Rhahzadh was slain and the remaining Sasanians retreated.

Continuing south along the Tigris he sacked Khosrow's great palace at Dastagird and was only prevented from attacking Ctesiphon by the destruction of the bridges on the Nahrawan Canal. Discredited by this series of disasters, Khosrow was overthrown and killed in a coup led by his son Kavad II, who at once sued for peace, agreeing to withdraw from all occupied territories. The Sassanian civil war significantly weakened the Sassanian Empire, contributing to the Islamic conquest of Persia.