It was about eight centuries before Buddhism, debased and corrupted, tainted with Siva worship and loaded with all the ghastly paraphernalia of a savage demonology, had been driven from India across the Himalayas, that the Star of Bethlehem had guided men from the East to the cradle of the Christian faith--a faith so like Buddhism in its ethical teaching and so unlike in its spiritual conceptions,--and during those eight centuries Christianity had already been spread by Apostles and missionaries through the broad extent of High Asia. Thereupon arose a new propaganda which, spreading outwards from a centre in south-west Arabia, finally set all humanity into movement, impelling men to call the wide world to a recognition of Allah and his one Prophet by methods which eventually included the use of fire and sword. The rise of the faith of Islam was nearly coincident (so far as India was concerned) with the fall of Buddhism. Thenceforward the gentle life-saving precepts of Gautama were to be taught in the south, and east, and north; in Ceylon, Burma, China, and Mongolia after being first firmly rooted in Tibet and Turkistan, but never again in the sacred groves of the land of their birth. And this raging religious hurricane of Islam swept all before it for century after century until, checked at last in Western Europe, it left the world ennobled by many a magnificent monument, and, by adding to the enlightenment of the dark places of the earth, fulfilled a mission in the development of mankind. With it there arose a new race of explorers who travelled into India from the west and north-west, searching out new ways for their commerce, and it is with them now and their marvellous records of restless commercial activity that we have to deal. Masters of the sea, even as of the land, no military and naval supremacy which has ever directed the destinies of nations was so widespread in its geographical field of enterprise as that of the Arabs. The whole world was theirs to explore. Their ships furrowed new paths across the seas, even as their khafilas trod out new highways over the land; and at the root of all their movement was the commercial instinct of the Semite. After all it was the eternal question of what would pay. Their progenitors had been builders of cities, of roads, of huge dams for water storage and irrigation, and directors for public works in Europe, Asia, and Africa. The might of the sword of Islam but carved the way for the slave-owner and the merchant to follow. Thus it is that mediæval records of exploration in Afghanistan and Baluchistan are mostly Arab records; and it is from them that we learn the "open sesame" of India's landward gates, long ere the seaports of her coasts were visited by European ships.