Also, Hinduism developed it's own evangelical wing in Buddhism, giving it a more easily propagated form. Apparently modern Hinduism is a relatively recent (recent meaning within the past 2000 years or so) reaction to a swing away from Buddhism which was the dominant form of Hinduism for a thousand years or so (c.f. the arrival of Christianity coinciding with the final swamping of Buddhism in S. India). When you deal with Asia, you deal in Deep Time, as far as a human timescale goes.