History of Wars Summary 19 - Roman-Persian Wars 9: The War of Attrition Between Rome and Persia

With Heraclius' counterattack, Rome regained most of the eastern territories it had lost, but the prolonged war significantly weakened both empires. After Khosrow II was deposed in 628, the Sasanian dynasty fell into a power struggle and political turmoil. The newly empowered Kavad II made a peace treaty with Rome and returned the occupied territories. Heraclius restored Roman rule in Syria, Egypt, and Mesopotamia. However, shortly after achieving victory, a new threat emerged. The Islamic forces rising from Arabia rapidly expanded and began attacking the borders of both empires. After 634, Arab armies attacked Syria and Palestine, and the Roman army suffered a major defeat at the Battle of Yarmouk. The Sasanian dynasty also lost territory after defeats at the Battle of Qadisiyyah and the Battle of Nihavand. The long Roman-Persian wars ultimately exhausted both nations, leaving them in a state where they could not effectively respond to the attacks of the new power.