The Battle of Sarus was a battle fought between the East Roman (Byzantine) army, led by Emperor Heraclius

Heraclius

Heraclius was Byzantine Emperor from 610 to 641.He was responsible for introducing Greek as the empire's official language. His rise to power began in 608, when he and his father, Heraclius the Elder, the exarch of Africa, successfully led a revolt against the unpopular usurper Phocas.Heraclius'...

, and the Persian general Shahrbaraz

Shahrbaraz

Shahrbaraz or Shahrwaraz was a general, with the rank of Eran Spahbod under Khosrau II . His name was Farrokhan, and Shahrbaraz was his title...

. 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

Constantinople

Constantinople was the capital of the Roman, Eastern Roman, Byzantine, Latin, and Ottoman Empires. Throughout most of the Middle Ages, Constantinople was Europe's largest and wealthiest city.-Names:...

, where his forces would take part in its siege

Siege of Constantinople (626)

The Siege of Constantinople in 626 by the Avars, aided by large numbers of allied Slavs and the Sassanid Persians, ended in a strategic victory for the Byzantines...

 together with the Avars

Eurasian Avars

The Eurasian Avars or Ancient Avars were a highly organized nomadic confederacy of mixed origins. They were ruled by a khagan, who was surrounded by a tight-knit entourage of nomad warriors, an organization characteristic of Turko-Mongol groups...

. The battle ended in a nominal victory for the Byzantines, but Shahrbaraz withdrew in good order, and was able to continue his advance through Asia Minor

Asia Minor

Asia Minor is a geographical location at the westernmost protrusion of Asia, also called Anatolia, and corresponds to the western two thirds of the Asian part of Turkey...

towards Constantinople.