The Last Great War of Antiquity pushed two empires to the brink of collapse.
The Byzantine–Sasanian War of 602–628 was a decades-long struggle that reshaped the Middle East. By the time the dust settled, both empires were so depleted of human and material resources that they were left defenseless against the rapid, transformative rise of the Islamic Rashidun Caliphate in the 630s.
The conflict began in 602 after the Byzantine emperor Maurice was murdered by his rival Phocas. Khosrow II, the Sasanian king, used the death of his former ally as a pretext for war. For two decades, the Persians held the upper hand, systematically conquering the Levant, Egypt, and parts of Anatolia. By 617, Persian forces had reached Chalcedon, placing them within sight of Constantinople and forcing the Byzantine state to consider relocating its government to Carthage.
Heraclius, who seized the throne in 610, faced a dire situation. To fund a counter-offensive, he implemented extreme fiscal measures, including halving official salaries, levying heavy fines, and stripping precious metals from monuments and the Hagia Sophia. In 622, he launched a daring campaign, abandoning traditional supply lines to strike directly into the Persian heartland. His victory at the Battle of Nineveh in 627 finally broke the Sasanian military, forcing the war-torn empire to seek peace.
The war’s legacy was not just the exhaustion of two superpowers but a fundamental shift in the regional order. The loss of Egypt, a vital source of grain for Constantinople, forced the abolition of the city's free grain ration in 618. While Heraclius secured a military triumph, the long-term cost was catastrophic. The subsequent emergence of the Rashidun Caliphate saw Muslim armies swiftly conquer the Levant, Mesopotamia, and Egypt, leading to the total fall of the Sasanian Empire and a permanent reduction in Byzantine power.
