This policy of the Papacy to make itself the world monarchy had a direct bearing upon the crusades and facilitated the enterprise. The astute mind of Hildebrand saw that a movement which should combine the Catholics of all countries in Europe under his command would immensely augment his prestige as their great overlord. During his pontificate there opportunely arrived at Rome messengers from the Greek emperor at Constantinople, beseeching the aid of Western Christendom in expelling the Turks, who were menacing the capital of the East. Hildebrand, consistently with his policy, prescribed as the condition of such aid the recognition on the part of the Greek Church of the headship of the Roman pontiff. But in this demand he overshot the mark, while at the same time the apathy of the Latin Christians towards their Greek brethren, and his own controversy with the German emperor, left him no opportunity to launch the movement. It was left to Urban II., his second successor in the pontificate, to undertake the great adventure. As Dean Milman remarks, “No event could be more favorable or more opportune for the advancement of the great papal object of ambition, the acknowledged supremacy over Latin Christendom, or for the elevation of Urban himself over the rival Pope [Guibert] and the temporal sovereign, his enemies.” CHAPTER VII. THE MOHAMMEDAN MENACE—THE RISE OF ISLAM—SARACENS—TURKS. The rapid rise and wide-spread conquest of Mohammedanism make one of the most startling phenomena of history. If its story excites our wonder in these days, while we are watching its decadence, we may imagine the consternation wrought when its swarming hosts, with the prestige of having conquered all western Asia, were breaking through the barriers of Christendom. We shall greatly mistake this movement if we regard it as a mere irruption of brute force such as characterized the assaults of the barbarians upon the Roman empire. The teachings of Mohammed, gross as they appear in contrast with either primitive or modern Christianity, contained elements which appealed to far nobler sentiments than those entertained by the pagans of northern Europe, or those current in the age of the Prophet among the people of his own race. Compared with these, Islamism was a reformation, and enthused its adherents with the belief that they fought for the advancement of civilization as well as for the rewards of paradise. The central thought of Islamism is the unity of the Godhead, and its first victory was the obliteration of polytheism among the tribes of Arabia.