The Byzantine–Sassanid War of 602–628 is the…
592 CE to 603 CE
The Byzantine–Sassanid War of 602–628 is the final and most devastating of the series of wars fought between the Roman (Byzantine) Empire and the Sassanian Empire of Persia.
The previous war between the two powers had ended in 591 after Emperor Maurice helped the Sassanid king Khosrau II regain his throne.
When Maurice is murdered in 602 by his political rival Phocas, Khosrau declares war, ostensibly to avenge the death of Maurice.
This will become a decades-long conflict, the longest war in the series.
