My favorite Chess book is "Chess: First Steps" by Bott & Morrison, (c) 1958. It has some particularly wicked illustrations by Patricia Lindsay which are quite memorable. Anyway, the authors state, "It was first played in India, and from there traveled across mountains and valleys to the great Persian Empire. The Arabs conquered Persia, and in their travels brought the game to the rest of Europe through Spain."

I think the India "Chaturanga" version included elephant regiments, which are very cool! And there are rumors that they originally also used random dice rolls to determine which piece got moved in each round ... whoa, wait a minute, that sounds like the D&D precursor "Chainmail" ... could it be that D&D is based on a revival of the original Chess wargame concept? Yeah, I guess after 1400 or so years I would expect to see one or two changes. I don't know if there is any historical evidence of an "early release", however.