Byzantine-Sasanian War of 602-628

The Byzantine-Sasanian War of 602 to 628 was the final and most destructive of the centuries-long series of wars fought between the Byzantine Empire and Sasanian Persia, triggered after the Persian king Khosrow II used the murder of the Byzantine emperor Maurice as a pretext to invade Byzantine territory. Persian forces achieved sweeping early successes, overrunning Byzantine Syria, Palestine and Egypt and advancing through Anatolia to besiege Constantinople itself in 626, in the same year the city also withstood a coordinated Avar and Slavic siege from the European side. Byzantine emperor Heraclius reversed the war's course with a series of campaigns launched deep into Persian territory from 624 onward, culminating in a decisive victory at the Battle of Nineveh in 627 that forced Khosrow's overthrow and a Persian peace restoring all captured Byzantine lands. Both empires emerged from the war financially and militarily exhausted, a weakness historians widely credit as a major factor enabling the rapid Arab Muslim conquests of the following decade.