[Sidenote: Mohammed, 571-632.] 25. Just as Gregory the Great was dying in Rome, leaving to his successors a great heritage of spiritual and temporal influence, a young Arab in far-off Mecca was meditating upon the mysteries of life and laying the foundation of a religious power rivaling even that of the popes. Before the time of Mohammed the Arabs had played no important part in the world's history. The scattered tribes were at war with one another, and each worshiped its own gods, when it worshiped at all. But when the peoples of the desert accepted Mohammed as their prophet and his religion as theirs, they became an irresistible force for the dissemination of the new teaching and for the subjugation of the world. [Sidenote: The Hejira, 622.] Mohammed came of a good family, but was reduced by poverty to enter the employ of a rich widow, named Kadijah, who fell in love with him and became his wife. She was his first convert and kept up his courage when few among his fellow-townsmen in Mecca would believe in his visions or accept the teachings which he claimed to receive direct from the angel Gabriel. Finally he discovered that his many enemies were planning to kill him, so he fled to the neighboring town of Medina, where he had friends. His flight (the Hejira), which took place in the year 622, was taken by his followers as the beginning of a new era,--the year one, as Mohammedans reckon time. A war ensued between the people of Mecca and those in and about Medina who supported Mohammed. It was eight years before he reëntered Mecca, the religious center of Arabia, with a victorious army. Before his death in 632 he had received the adhesion of all the Arab chiefs, and his faith, Islam (which means _submission to God_), was accepted throughout the Arabian peninsula. [Sidenote: The Koran and the religion of Mohammed.]