Reading a comment made on this site, I saw something very curious:
Why not blame it on the ancient Hindu belief that traveling overseas pollutes a person irredeemably, thereby stunting the growth of Indian naval technology and ensuring Europeans came to India rather than vice versa?
Searching on Google, I find quite a few people debating whether there are current rules against overseas travel, or what the penalties are, but I haven't been able to find anything about this belief in ancient days.
I know that Hinduism did spread to Indonesia at one point, so I imagine there was no prohibition against overseas travel in those days. So, to be more specific:
When did Hinduism first prohibit overseas travel, and when did it stop prohibiting overseas travel?