The Battle of Sarus was a battle fought in April 625 between the East Roman (Byzantine) army, led by Emperor Heraclius, and the Persian general Shahrbaraz. After a series of maneuvres, the Byzantine army under Heraclius, which in the previous year had invaded Persia, caught up with Shahrbaraz's army, which was heading towards the Byzantine capital, Constantinople, where his forces would take part in its siege together with the Avars.