Byzantine emperor (610-641), famous during the crusade period for his recovery of the relic of the True Cross from the Persians.
Heraclius came to power after overthrowing his predecessor, Phokas. At the time of his accession, Byzantium faced major military threats from the Slavs and Avars in the Balkans and from the Persians in the eastern provinces. In 614, the Persians took Jerusalem, capturing its most holy relic, the True Cross. By 629, Syria, Palestine, and Egypt had fallen, and Constantinople was deprived not only of fiscal revenues but substantial grain supplies. After making peace with the Avars by paying them a vast tribute, Heraclius turned his attention eastward and campaigned far into Persia. In 627 internal strife led to the overthrow of the Persian shah, Chosroes II. The True Cross was returned in triumph to Jerusalem in 630. However, the end of Heraclius’s reign was marked by the rise of Islamic power, culminating in the defeat of his armies at the battle of the Yarmuk in 639. By 642, Syria, Palestine, Mesopotamia, and Egypt had been overrun by the Arabs. In 636 Heraclius returned to Constantinople, where, in the last years of his reign, he became increasingly unpopular; criticism centered on his unsuccessful attempts to resolve theological disputes and on his marriage to his niece Martina.
Heraclius’s defense of the Holy Land and his recovery of the True Cross meant that he was sometimes regarded as a kind of proto-crusader in later ages, notably by the twelfth- century crusade chronicler William of Tyre, who began his history of Outremer with an account of the wars fought by the emperor.