The stream of pilgrimage was full until the reign of Heraclius. Then the Persian king, Chosroes, carried his arms through Syria and Palestine to Egypt. The fire-worshipers defiled the holy city by their authority and their worship. They tainted and robbed the churches, and carried off what was believed to be the cross of the crucifixion, which had been guarded by the Church of the Resurrection. [Sidenote: _Return of the Cross_] The wailing of the Christian world over this loss strengthened the courage of Heraclius through ten years of reverses, and aided in the late but full victory which not only brought back to Jerusalem the enslaved Christians but the Cross of Calvary, as the most glorious of trophies. The emperor himself bore this barefooted to the summit of Calvary, and at Constantinople received the congratulations of the Christian world. Jerusalem was soon, however, to feel the weight of a new and heavy hand. [Sidenote: _Rise of Mahomet_] [Sidenote: _Greek Empire Corrupt_] In Arabia a religion arose with a singular power of advance, which it retains to this day. The union of the spiritual with the material, of the sensual with a fatalistic theology, made the followers of Mahomet eager for heaven by way of the battle-field. The Jews had now no unity; Christianity had become divided into sects cursing each other; the Persian Empire had exhausted itself; the Greek Empire was wasted with its own corruptions. The way was open for the stern, sober, and, in all respects but one, self-denying followers of Mahomet. Until they learned to navigate they swept the eastern and southern coasts of the Mediterranean. They early overwhelmed Palestine. Becoming masters of maritime peoples, they conquered even to Spain; were held at bay for a while by Constantinople; came even under the walls of Vienna, and were at length beaten back by Charles Martel. [Sidenote: _Jerusalem Sacred to Mohammedans_] [Sidenote: _Jerusalem Taken by Omar_] Jerusalem was almost as sacred a city to the Mohammedans as to the Christians. Their prophet had visited it, and had journeyed to heaven from it. Attacked by the soldiers of Omar shortly after the death of the prophet, the Christians endured the horrors of a siege for four months, resisting armies which claimed the city as theirs by the promises of God. Omar came to receive the keys of the exhausted city, and Christians cried out in agony as the chief infidel defiled by his presence the Holy Sepulcher. They were permitted to worship, but not openly to exhibit their crosses and sacred books. Their conqueror erected a mosque on the site of the temple. This was more than the breaking heart of the Christian patriarch could bear. He died bewailing the sorrows and desolation of the city of the Great King. [Sidenote: _Omar Checks Persecution_]