"There is hardly an example of a mass movement achieving vast proportions and a durable organization solely by persuasion. ...It was the temporal sword that made Christianity a world religion. Conquest and conversion went hand in hand... Where Christianity failed to gain or retain the backing of state power, it achieved neither a wide nor a permanent hold. ..."The most flourishing periods for Mohammedanism have been at the times of its greatest political ascendency..." The Reformation made headway only when it gained the backing of the ruling prince or the local government. In the case of the French Revolution, "It was the armies of the Revolution, not its ideas, that penetrated throughout the whole of Europe." ...The threat of communism at present does not come from the forcefulness of its preaching but from the fact that it is backed by one of the mightiest armies on earth."