How did belief in monotheism develop?

Monotheism started back in the Mesopotamia Era. It started when Moses came in to power and he supported Monotheism, which is pretty much believing that their is only one god. Moses believed Yahweh, and said that he was the one and only God. When Moses said all other gods were just imagination. When this got around it started spreading the idea of Monotheism Whoooo i can't believe i just wrote that, i feel so smart. Thank you A.P. World history. This wonderful description is by moi, im david and im 15 years old