1. (pre-societal/paleolithic/early human history) the belief in beings more powerful than ourselves is born from ignorance of the world around us. it serves as an explanation for physical phenomenon, thunderstorms, drought, eclipses, rain, bounty.... a key aspect of this early god-driven dynamic, and something that supports my second point, is the existence of 'many' gods. Human beings, the human mind, had not yet evolved to point where 'self' was a defining characteristic. The knowledge of actually being 'alive' was not understood.
2. (early society) Hunter-gatherers begin to form the nascent constructs that would give birth to modern societies. Human beings begin to evolve socially at an exponential rate in comparison to earlier ancestors and with that, began to define themselves as individuals. As the definition of 'us' began to materialize, so did the definition of our early gods. We went from the many gods of early cavemen, to the more individualized gods of Greek and Roman culture. The correlation of our own evolution to the evolution of our gods is an extremely powerful argument against the existence of any gods at all. Simpy put, as we evolved, so did our gods.
3. (late Greek to mid Roman Empire) the idea of self is now fully realized socially. People 'know' that they are alive, that they are individuals and unique. Not surprisingly, our Gods suddenly become individual and unique; the Greek set of Gods, the similar Roman set... this evolves further and the idea of many gods becomes intellectually obsolete. Judaism and Christianity become popular. The idea of 'one' god for 'one' person, my God, replaces the earlier ideas of many gods. Simpy put, as we evolved, so did our gods.
4. (late Roman Empire and beyond) the idea of many gods disappears completely. the philosophy of 'self' and 'everlasting life' becomes the dominant principle of then and future religions. the power of that is effectively put to use by the few to control the many.
5. (now) because of the basic human need to understand and the selfish desire (we know that we're alive, how could we possibly want to give that life up) to live forever .. religion persists.