During the period of his life at Medina, Muhammed abandoned his original idea of preaching the doctrines which Moses and Jesus had proclaimed. This new development was the outcome of a struggle with Judaism following upon an unsuccessful attempt at compromise. In point of fact Judaism and Christianity were as widely different from one another as they were from his own teaching and he was more than ever inclined to regard as his special forerunner, Abraham, who had preceded both Moses and Jesus, and was revered by both religions as the man of God. He then brought Abraham into connection with the ancient Meccan Ka'ba worship: the Ka'ba or die was a sacred stone edifice, in one corner of which the "black stone" had been built in: this stone was an object of reverence to the ancient Arabs, as it still is to the Muhammedans. Thus Islam gradually assumed the form of an Arab religion, developing universalist tendencies in the ultimate course of events. Muhammed, therefore, as he was the last in the ranks of the prophets, must also be the greatest. He epitomised all prophecy and Islam superseded every revealed religion of earlier date. Muhammed's original view that earlier religions had been founded by God's will and through divine revelation, led both him and his successors to make an important concession: adherents of other religions were not compelled to adopt Islam. They were allowed to observe their own faith unhindered, if they surrendered without fighting, and were even protected against their enemies, in return for which they had to pay tribute to their Muslim masters; this was levied as a kind of poll-tax. Thus we read in the Qoran (ix. 29) that "those who possess Scriptures," i.e. the Jews and Christians, who did not accept Islam were to be attacked until they paid the _gizja_ or tribute. Thus the object of a religious war upon the Christians is not expressed by the cry "Death or Islam"; such attacks were intended merely to extort an acknowledgment of Muhammedan supremacy, not to abolish freedom of religious observance. It would be incorrect for the most part to regard the warrior bands which started from Arabia as inspired by religious enthusiasm or to attribute to them the fanaticism which was first aroused by the crusades and in an even greater degree by the later Turkish wars. The Muhammedan fanatics of the wars of conquest, whose reputation was famous among later generations, felt but a very scanty interest in religion and occasionally displayed an ignorance of its fundamental tenets which we can hardly exaggerate. The fact is fully consistent with the impulses to which the Arab migrations were due. These impulses were economic and the new religion was nothing more than a party cry of unifying power, though there is no reason to suppose that it was not a real moral force in the life of Muhammed and his immediate contemporaries.