to give more than occasional annoyance to well-guarded frontiers.
It may be added that the northwestern gates of India were soon to be double-locked against outside invasion. For while this independent Afghan kingdom formed an excellent barrier against all attempts to break into India from Central Asia by the only land routes through which an army can enter, the Afghans themselves were barred off from the Panjab about this time by the Sikhs. The rapid expansion of the power of the Sikhs, who are Hindu sectaries, illustrates the almost invariable process by which every great proselytizing movement in Asia tends to acquire a political and militant character. The two tendencies, of course, interact on each other, for while a religious revival is sure to rally under its flag a good deal of political discontent, civil commotions, on the other hand, usually set up the standard and appeal to the sanction of religious enthusiasm.
Toward the end of the last century, the votaries of the Sikh faith, fanatically hostile to Islam and in open revolt against their Mohammedan rulers, were gathering into a close association, whose stubborn fighting qualities and rapid political development under military chiefs were extending their power across upper India from the Sutlaj to the Indus. They were thus erecting a second and inner barricade against inroads from Central Asia, which cut off the communications between Islam in India and the rest of the Mohammedan world.
