In 602, the final war between the Byzantine Empire and its eastern rival the Persian Empire (Sasanid Empire) broke out. In 613 the Persians invaded the Levant and the Jews revolted against the Byzantines, hoping to secure autonomy for Jerusalem. The following year Persian-Jewish forces captured Caesarea and Jerusalem, destroying its churches, massacring its Christian population, and taking the True Cross and other relics as trophies. The Jews gained dominance over Jerusalem, but the Persians found it more expedient to side with the Christians who constituted the overwhelming majority of the population and in 617 the Persians returned the city to them. Meanwhile, the Roman emperor Heraclius began a successful counter-offensive. By 627/8 he was advancing into the Persian heartland. The Persians sued for peace and had to return the Roman provinces they had captured and the stolen relics. In March 629, Heraclius triumphantly returned the True Cross to Jerusalem. Heraclius had promised the Jews pardon for their earlier treachery but the Christians had not forgotten the Jews' atrocities. At their insistence, Heraclius expelled the Jews from Jerusalem and had those involved in the uprising executed.