What was the meaning of all that whisper of fear that ran round the West under the shadow of Islam, and fills every old romance with incongruous images of Saracen knights swaggering in Norway or the Hebrides? Why were men in the extreme West, such as King John if I remember rightly, accused of being secretly Moslems, as men are accused of being secretly atheists? Why was there that fierce alarm among some of the authorities about the rationalistic Arab version or Aristotle? Authorities are seldom alarmed like that except when it is too late. The answer is that hundreds of people probably believed in their hearts that Islam would conquer Christendom; that Averroes was more rational than Anselm; that the Saracen culture was really, as it was superficially, a superior culture. Here again we should probably find a whole generation, the older generation, very doubtful and depressed and weary. The coming of Islam would only have been the coming of Unitarianism a thousand years before its time. To many it may have seemed quite reasonable and quite probable and quite likely to happen. If so, they would have been surprised at what did happen. What did happen was a roar like thunder from thousands and thousands of young men, throwing all their youth into one exultant counter-charge; the Crusades. It was the sons of St. Francis, the Jugglers of God, wandering singing over all the roads of the world; it was the Gothic going up like a flight of arrows; it was the waking of the world. In considering the war of the Albigensians, we come to the breach in the heart of Europe and the landslide of a new philosophy that nearly ended Christendom for ever. In that case the new philosophy was also a very new philosophy; it was pessimism. It was none the less like modern ideas because it was as old as Asia; most modern ideas are. It was the Gnostics returning; but why did the Gnostics return? Because it was the end of an epoch, like the end of the Empire; and should have been the end of the Church. It was Schopenhauer hovering over the future; but it was also Manichaeus rising from the dead; that men might have death and that they might have it more abundantly.