My own view of this question is that though there are certain streams of tendency, though there is a certain steady and orderly evolution that it is impossible in the long run to resist, yet individual action and even mere accident have borne a very great part in modifying the direction of history. It is with History as with the general laws of Nature. We can none of us escape the all-pervading force of gravitation, or the influence of the climate under which we live, or the succession of the seasons, or the laws of growth and of decay; yet man is not a mere passive weed drifting helplessly upon the sea of life, and human wisdom and human folly can do and have done much to modify the conditions of his being. It is quite true that religions depend largely for their continued vitality upon the knowledge and intellectual atmosphere of their time; but there are periods when the human mind is in such a state of pliancy that a small pressure can give it a bent which will last for generations. If Mohammed had been killed in one of the first skirmishes of his career, I know no reason for believing that a great monotheistic religion would have arisen in Arabia, capable of moulding for more than twelve hundred years not only the beliefs, laws, and governments, but also the inmost moral and mental character of a vast section of the human race. Gibbon was probably right in his conjecture that if Charles Martel had been defeated at the famous battle near Tours, the creed of Islam would have overspread a great part of what is now Christian Europe, and in that case it might have ruled over it for centuries. No one can follow the history of the conversion of the barbarians to Christianity without perceiving how often a religion has been imposed in the first instance by the mere will of the ruler, which gradually took such root that it became far too strong for any political power to destroy. Persecution cannot annihilate a creed which is firmly established, or maintain a creed which has been thoroughly undermined, but there are intermediate stages in which its influence on national beliefs has been enormously great. Even at the Reformation, though more general causes were of capital importance, political events had a very large part in defining the frontier line between the rival creeds, and the divisions so created have for the most part endured.