1500 BCE was conjured up by Max Muller, and is papably WRONG. Bhagawat Purana has astronomical data which point that the said events happened earlier than 3100. Max Muller just dismissed it. How? Only he knows. Or maybe you too. If a certain astronomical event is described in detail and turns out to verifiable correct, what do you conclude? That SOMEONE did observe it and recorded it. Alternative is this: Some one, a SUPER BRAIN cooked up the data after 1500 BCE. Back calculation, in other words. Know how hard it was do so 3500 years ago? Now Sanskrit appears in 1500 BCE, that so? How do you explain the astronomical events in Rig Veda, events as old as 6000 years ago. Another. It appeared in 1500 BCE, and very quickly, very fast, Vedas were complied, Purana appeared, Upanishads appeared, other secular treatises [medicine, law etc] appeared, all by the time of Buddha!!! Just in 800-900 years? Do you even know how many lines and words those books contain? Btw, RV is in archaic Sanskrit and has never been redacted in Panini grammar. Reason? There was a taboo on its trading, hence writing it down, and thus came down by oral traditions. Now please do not tell me that RV was written in 1200 BCE or so. PS: If you reply, please don't put on your mod cap. That would be intolerance of dissenting view.