The Byzantine and Sassanian (Persian) empires were the two superpowers of the Near East for centuries.

They were engaged in a long series of conflicts over control of territory in the Middle East and the Caucasus.

The final and most devastating war between them lasted from 602 to 628 CE.

This war began with a massive Sassanian invasion that led to the conquest of Byzantine Syria, Egypt, and Anatolia.

The Sassanian army even reached the outskirts of Constantinople.

The Byzantine Emperor Heraclius launched a remarkable counter-offensive, taking the war deep into the Persian heartland.

The decisive Byzantine victory at the Battle of Nineveh in 627 CE led to the collapse of the Persian war effort.

The war ended with both empires utterly exhausted financially and militarily.

This mutual exhaustion created a power vacuum in the region.

The weakness of both empires after this war was a key factor in the rapid success of the early Muslim conquests just a few years later.