"The Mohammedan invasions put an end to the great age of Hindu philosophy. The assaults of the Moslems, and later of the Christians, upon the native faith drove it, for self-defense, into a timid unity that made treason of all debate, and stifled creative heresy in a stagnant uniformity of thought. By the twelfth century the system of the Vedanta, which in Shankara had tried to be a religion for philosophers, was reinterpreted by such saints as Ramanuja (ca. 1050) into an orthodox worship of Vishnu, Rama and Krishna. Forbidden to think new thoughts, philosophy became not only scholastic but barren; it accepted its dogmas from the priesthood, and proved them laboriously by distinctions without difference, and logic without reason."