On this day in AD 641, Heraclius, one of the most heroic — and tragic — late Roman emperors, died. He ruled for 30 of the most crisis-plagued years the Roman empire had ever experienced.
Under the rule of his predecessor, the cruel usurper Phocas, the Slavs had overrun the Balkans. At the same time, Syria, Egypt, and much of Asia Minor had been conquered by the Persians. The Persian king Chosroes II had even sacked Jerusalem, taking the True Cross back to Persia with him.
Rising from Africa where his father was exarch, Heraclius overthrew Phocas, but was faced with the daunting task of saving the empire from powerful enemies attacking on two fronts. Melting down gold given to him from the churches, Heraclius recruited and trained a new army. Rather than await the coming siege of the capital, Heraclius took the war to the Persians, defeating them in several pitched battles.
His campaign became a crusade. It was a fight to the death between the Christian Romans and fire-worshiping Persians — and in the end, the great Persian empire of the Sassanids lay prostrate on the ground. Heraclius recovered the relics from Jerusalem, and in AD 630, he returned to Jerusalem carrying the True Cross before him.
But his triumph was not long lived. Within six years, the Romans were again defeated in Palestine at Yarmuk by an invading army driven by a new power sweeping out of Arabia—Islam. By the end of his life, nearly all Heraclius had fought so hard to re-conquer had again been swept away, never to be recovered by the empire.
More detailed information on the eventful reign of Heraclius may be found here.