Siege of Edessa
610 CE.
Shown on the map at 37.150°, 38.800°.
The Byzantine–Sasanian War of 602–628, also called the Last Great War of Antiquity, was fought between the Byzantine Empire and the Sasanian Empire. It was the final and most devastating conflict of the Roman–Persian wars (54 BC – AD 628). The previous war between the two powers had ended in 591 after the emperor Maurice helped the Sasanian king Khosrow II regain his throne. In 602, Maurice was murdered by his political rival Phocas. Khosrow declared war, ostensibly to avenge the death of the deposed emperor Maurice. This became a decades-long conflict, the longest war in the series, and was fought throughout the Middle East, the Aegean Sea, and before the walls of Constantinople itself. From 602 to 622, the Sassanians gradually conquered much of the Levant, parts of Anatolia, and—for the first time—Egypt and several islands in the Aegean Sea. The counter-attacks of the new Byzantine emperor Heraclius from 622 to 626 eventually forced the Persians onto the defensive. Allied with the Avars and Slavs, the Persians attempted to take Constantinople in 626, but were defeated. In 627, allied with Turks, Heraclius invaded the heartland of Persia.
Text from the Wikipedia article Byzantine–Sasanian War of 602–628, licensed CC BY-SA 4.0.