Some of the Arabs being offended at the new teaching, wanted to put him to death; and he fled from his home at Mecca. On his way he was so closely pursued as to be forced to hide in a cave. His enemies were just going to search the cave, when they saw a spider's web over the mouth, and fancied this was a sign that no one could have lately entered it, so they passed by and left him safely concealed. In his anger at this persecution, be declared that the duty of a true Mahometan was to spread his religion with the sword; and calling his friends round him, they fought so bravely that he won back Mecca, and conquered the whole of Arabia. They did not persecute Christians, but they kept them down and despised them; and any Mahometan who changed his religion, was always put to death. Mahomet called himself Khalif, and ruled for ten years at Mecca, where he died and was buried. Mahometans go on pilgrimage to Mecca, and always turn their faces thither when they pray at sunrise or sunset, throwing water over themselves, or sand if they cannot get water. The Khalifs who came after Mahomet, went on conquering. The chief tribe of the Arabs was called Saracens; and this was the name given to the whole race whom God had sent to punish the Christian world. The Holy City itself, and all the sacred spots, were permitted to fall into their hands; and though they did not profane the churches, the Khalif Omar built a great mosque, or Mahometan place of worship, where the Temple had once been, so as quite to overshadow the Church of the Holy Sepulchre. They conquered Persia, and spread their religion through that country, putting down the fire worshippers; they seized almost all Asia Minor, where the heretical Christians too easily became Mahometans, and they obtained possession of Egypt, and the great library at Alexandria, where they burnt all the collection of books, because they said, "If they taught the same as the Koran, they were useless, if otherwise, they were mischievous." Then from Egypt they spread all along the north coast of Africa, where the Roman dominion had once been, and were only grieved that the waves of the Atlantic Ocean kept them from going further to the west.