No greater misfortune could have occurred both for Islam and for the world at large. For Islam it meant the rule of dull-witted bigots under which enlightened progress was impossible. Of course Islam did gain a great accession of warlike strength, but this new power was so wantonly misused as to bring down disastrous repercussions upon Islam itself. The first notable exploits of the immigrant Turkish hordes were their conquest of Asia Minor and their capture of Jerusalem, both events taking place toward the close of the eleventh century[4]. Up to this time Asia Minor had remained part of the Christian world. The original Arab flood of the seventh century, after overrunning Syria, had been stopped by the barrier of the Taurus Mountains; the Byzantine Empire had pulled itself together; and thenceforth, despite border bickerings, the Byzantine-Saracen frontier had remained substantially unaltered. Now, however, the Turks broke the Byzantine barrier, overran Asia Minor, and threatened even Constantinople, the eastern bulwark of Christendom. As for Jerusalem, it had, of course, been in Moslem hands since the Arab conquest of A.D. 637, but the caliph Omar had carefully respected the Christian "Holy Places," and his successors had neither persecuted the local Christians nor maltreated the numerous pilgrims who flocked perennially to Jerusalem from every part of the Christian world. But the Turks changed all this. Avid for loot, and filled with bigoted hatred of the "Misbelievers," they sacked the holy places, persecuted the Christians, and rendered pilgrimage impossible. The effect of these twin disasters upon Christendom, occurring as they did almost simultaneously, was tremendous. The Christian West, then at the height of its religious fervour, quivered with mingled fear and wrath. Myriads of zealots, like Peter the Hermit, roused all Europe to frenzy. Fanaticism begat fanaticism, and the Christian West poured upon the Moslem East vast hosts of warriors in those extraordinary expeditions, the Crusades.