Byzantine Emperor. He was born in AD 575 and grew up in Roman Africa. In AD 608 he and his father, also called Heraclius, rebelled against the usurper Emperor Phocas and he was soon declared Emperor by the aristocrats of Constantinople. He then entered the city without resistance and executed Phocas. These were difficult times for the Empire, Phocas had left the Danube unprotected, the Sassanid Empire threatened war and the Persians had attacked Syria. After some initial losses to the Persians, he rebuilt the army and in AD 621 became the first Emperor to lead an army into battle since Theodosius I. He marched a force of fifty-thousand men across Asia-Minor and invaded Persia, defeating and killing the Persian leader Rhahzadh at the Battle of Ninevah. The Persian ruler Chosroes was deposed as Heraclius' army advanced and his successor, Kavadh II, restored all Byzantium's former territoties. Following this victory he adopted the ancient Persian title of "King of Kings" and from AD 629 began calling himself "Basileus", the Greek word for monarch. He was the first Emperor to abandon the traditional Roman title of "Augustus". He also replaced Latin with Greek as the official language of the Empire. In AD 630 he went on a barefoot pilgrimage to Jerusalem and restored the True Cross to the Church of the Holy Sepulchre following its removal by the Persians. The Empire now faced a new threat from the newly Islamic Arabs and by the time of his death Syria, Palestine and Egypt had been lost. He did, however, halt the Muslim advance into Asia Minor and secured Carthage for the Empire. He is remembered for his reform of the government and military and his reduction of corruption. When he died in AD 641, he left the Empire to be ruled jointly by Constantine III, Heraklonas and the Empress Martina.