^17:1 I do not forget that India has again and again been invaded and partially conquered by armies which poured into it through the North-Western passes. But these invasions, with the exception of that which Alexander the Great conducted, did little or nothing to promote spiritual intercourse between the Eastern and Western worlds. For, speaking generally, the invaders were too undeveloped and unenlightened to be able to assimilate the spiritual ideas of the land which they entered. The earlier invaders, who accepted Buddhism, precipitated the downfall of that religion in India by debasing and corrupting it till it lost its identity. The later invaders, who introduced Mahometanism into India, were debarred by their own bigotry from getting into touch with the profound faith which slumbered behind the "idolatry" of the conquered people. The North-Western passes have never, since the downfall of Hellenism in Central Asia, been an open door between East and West. The door has opened wide enough to admit invading armies, and after a time has closed, as it were, behind them. It is only through the gateway of the seas--now at last thrown open to all men--that sustained intercourse between the two worlds can be carried on.