The world of Islam became and long remained, the heir of the old Graeco-Roman culture and the preserver thereof. Thence was it that, alone of all the great heresies, Mohammedanism not only survived, and is, after nearly fourteen centuries, as strong as ever spiritually. In time it struck roots and established a civilization of its own over against ours, and a permanent rival to us.
Now that we have understood why Islam, the most formidable of heresies, achieved its strength and astounding success we must try to understand why, alone of all the heresies, it has survived in full strength and even continues (after a fashion) to expand to this day.
This is a point of decisive importance to the understanding not only of our subject but of the history of the world in general. Yet it is one which is, unfortunately, left almost entirely undiscussed in the modern world.
Millions of modern people of the white civilization – that is, the civilization of Europe and America – have forgotten all about Islam. They have never come in contact with it. they take for granted that it is decaying, and that, anyway, it is just a foreign religion which will not concern them. It is, as a fact, the most formidable and persistent enemy which our civilization has had, and may at any moment become as large a menace in the future as it has been in the past.