Heraclius

Heraclius and his father led a revolt in 608 against the emperor Phocas, and by 610 he held the throne. He inherited a catastrophic war with Persia: he lost the Battle of Antioch in 613, and the Persians took Syria and Egypt, shrinking the empire to Asia Minor. He rebuilt the military, drove them out, and in 627 smashed them at Nineveh, devastating Mesopotamia; the Persian Shah Khosrow II was overthrown and executed, and his son sued for peace. The empire was exhausted. Then the Arabs came: in 636 they defeated his brother Theodore in Syria and swept through Mesopotamia, Armenia, and Egypt in years. Heraclius instituted reforms that let his successors hold the line, opened talks with the Serbs, tried and failed to heal the Christian schism with monothelitism, and made Greek the state language. He died 11 February 641, having won an old war and lost a new one.