Such in personal conduct was the manner of men who sat on the eastern throne of the great Constantine during the seventh century: whom four-and-twenty Popes found themselves bound to acknowledge as “Christian kings and Roman princes”. What they were in this capacity, which was the first and greatest of all their duties, as recognised by the imperial laws, will be seen as the narrative proceeds. Under these men the Popes, utterly deprived of temporal power, in the midst of a province an outlying domain of a distant despot, had to maintain the unity of the Christian faith, and the independence of the Holy See as its guardian. In the midst of these things the chalifs of Mohammed broke upon the eastern empire, and severed from it its fairest provinces. It is requisite to follow closely the series of events, and the connection of times. Upon his accession to the throne in 603 Phocas had sent an embassy to the Persian emperor Chosroes, expressing his desire to maintain peace with him. But Chosroes under pretext of avenging his benefactor, the late emperor Mauritius, began a war which lasted more than four and twenty years, inflicted fearful sufferings on both empires, and had the most important consequences by leaving them in a state of great weakness to meet the assault of a new enemy, the Mohammedan chalifate. During the first eighteen years of this war, that is, from 604 to 622, the Greek empire suffered a series of defeats and disasters. Through the whole East, from the ruins of Babylon to the Bosphorus, cities were burnt and destroyed, the country ravaged and left without cultivation, the inhabitants slain or carried away into slavery. The Persians tore from the empire province after province—Armenia, Mesopotamia, Cappadocia. In 610 they came up to the walls of Chalcedon. The accession of Heraclius produced no pause in their destructive course. In 611 they took Edessa, Apamea, and Antioch. In 615 they plundered Palestine, and took Jerusalem. The Church of Gethsemane, on the Mount of Olives, and Constantine’s Basilica of the Holy Sepulchre were destroyed or burnt. Among the inhabitants carried away was the patriarch Zacharias. The Persians seized in plunder all that was valuable, and the priceless relic of the Holy Cross was taken away by the fire-worshipper Chosroes. The Sponge and the Lance were saved by the patrician Nicetas, who purchased them at a high price from a Persian soldier, and then brought them to Constantinople, where they were exposed for veneration of the faithful.