To Sumerians, and to later peoples in Mesopotamia as well, the world was controlled by gods and goddesses, who represented cosmic forces such as the sun, moon, water, and storms. Each city generally had a chief god or goddess, or sometimes several, with a large temple built in his or her honor. The king of the gods was Enlil, who was believed to rule over the gods just as the king of a city-state ruled his population. Almost as powerful were the gods of the sun, of storms, and of freshwater.

People believed that humans had been created to serve the gods and generally anticipated being well treated by the gods if they served them well. The best way to honor the gods was to make the temple as grand and impressive as possible because the temple’s size demonstrated the strength of the community and the power of its chief deity. Once it was built, the temple itself was often off-limits to ordinary people, who did not worship there as a spiritual community. Instead the temple was staffed by priests and priestesses who carried out rituals to honor the god or goddess. Kings and other political leaders might also visit the temple and carry out religious ceremonies from time to time, particularly when they thought the assistance of the gods was especially needed.

The peoples of Mesopotamia had many myths to account for the creation of the universe. According to one told by the Babylonians, in the beginning was the primeval sea, known as the goddess Tiamat, who gave birth to the gods. When Tiamat tried to destroy the gods, Marduk, the chief god of the Babylonians, proceeded to kill her and divide her body and thus created the sky and earth. These myths are the earliest known attempts to answer the question: How did it all begin?

In addition to stories about gods, the Sumerians also told stories about heroes and kings, many of which were eventually reworked into the world’s first epic poem, the Epic of Gilgamesh (GIL-guh-mesh). It recounts the wanderings of Gilgamesh — the semihistorical king of Uruk — and his search for eternal life, and it grapples with enduring questions about life and death, friendship, humankind and deity, and immortality.