The Persian Empire, the foundation of which by Cyrus the Great we are now celebrating, was dissolved as the result of the Greek invasion under Alexander; it was restored, some five and a half centuries later, by the native dynasty of the Sassanians, who like the Achaemenids before them, had their origins in the south-western province of Fars or Pars, which has given Iran the name by which it is known in the West. The Persian Empire thus restored disputed with the heirs of Alexander, the rulers of Rome and Byzantium, for the possession of Western Asia. The later phase of this struggle is referred to in the Koran: "The Greeks have been defeated in a land hard by: but after their defeat they shall defeat their foes." This is a reference to the war waged against the Byzantines by the Sassanian Emperor Khusrau Parviz, who in the course of a war of more than twenty years' duration, was to extend the boundaries of the Persian Empire to where they had lain in the days of Darius, on the shores of the Mediterranean and the Aegean; it is also a prophecy of the Byzantines' ultimate victory with the triumphal entry of Heraclius into Jerusalem in 629.