Humans create gods and goddesses, and unicorns and trolls, one has only to read history and mythology to know that. And if, god forbid, so to speak, you were to study anthropology you would understand why beliefs and religions evolved as part of each human group's culture. Belief is a social glue, and it identifies members absolutely as one of a specific culture. To be ostracized from a culture means you lose that unity with those people and you then must associate with others with other beliefs, and they immediately know you are an outsider. But back in 'those times', long before science and books, and we're talking thousands of years before the christian 'god' would appear, no one knew anything beyond the simplest, rudimentary things. Rather it seems it was a logical progression from the water and tree spirits of an even more primitive time, millennia before the christian or indian or whatever gods existed. Julian Jaynes makes an excellent case for 'gods' that have arisen from a leader's dreams or hallucinations.
Face it, we've been completely brainwashed since birth, to be honest about it. We've all been lied to and force-fed with beliefs by others who stand to gain from our belief, from parents to preachers to government officials. Yet look around today, we've supposedly evolved into 'thinking', 'aware' human beings, who can appreciate the beauty of the scientific method to provide a point of reference regarding 'reality', yet we still don't see any agreement upon anything, in fact it seems the opposite, that we exercise our creativity to create new beliefs and new gods.
Allow me to add this reference to Julian Jaynes, a very original thinker for sure, a pleasure to read:
Julian Jaynes - Wikipedia