causes, do not ignore the fact that it was Mohammed who opened the sluice gates. It would indeed be difficult to maintain that without his preaching the Arabs of the seventh century would have been induced by circumstances to swallow up the empire of the Sasanids and to rob the Byzantine Empire of some of its richest provinces. However great a weight one may give to political and economic factors, it was religion, Islâm, which in a certain sense united the hitherto hopelessly divided Arabs, Islâm which enabled them to found an enormous international community; it was Islâm which bound the speedily converted nations together even after the shattering of its political power, and which still binds them today when only a miserable remnant of that power remains.
The aggressive manner in which young Islâm immediately put itself in opposition to the rest of the world had the natural consequence of awakening an interest which was far from being of a friendly nature. Moreover men were still very far from such a striving towards universal peace as would have induced a patient study of the means of bringing the different peoples into close spiritual relationship, and therefore from an endeavour to understand the spiritual life of races different to their own. The Christianity of that time was itself by no means averse to the forcible extension of its faith, and in the community of Mohammedans which systematically attempted
