Putting aside the religious subject matter, there is a 3.0 book called Testament: Roleplaying in the Biblical Era. Good rules for alternate mage classes that work on astronomy. Valuable information and rules about Bronze Age culture.

A friend of mine used it to run a campaign, with basic reflavoring.

Iron Heroes often has a very primitive feel to it, even though there is no place in history it truly belongs.

Conan itself is a great game, built on a solid system.