The Sumerians practiced a polytheistic religion, with anthropomorphic gods or goddesses representing forces or presences in the world, in much the same way as later Greek mythology. According to said mythology, the gods originally created humans as servants for themselves but freed them when they became too much to handle.
Many stories in Sumerian religion appear similar to stories in other Middle-Eastern religions. For example, the Biblical account of the creation of man as well as Noah’s flood resemble the Sumerian tales very closely. Gods and Goddesses from Sumer have distinctly similar representations in the religions of the Akkadians, Canaanites, and others. A number of stories and deities have Greek parallels as well; for example, it has been argued by some that Inanna’s descent into the underworld strikingly recalls (and predates) the story of Persephone.
According to Sayce: Don “In historical Babylonia the gods were in the form of man. Man was created in the image of God because the gods themselves were men.”
Like the Pharaohs of Egypt or the emperors of Rome, the early kings of Semitic Babylonia were deified. And the deification took place during their life-time, in fact, so far as we can judge, upon their accession to the throne. In the eyes of their subjects they were incarnate deities, and in their inscriptions they give themselves the title of god.”