The Sumerians believed they could defeat death if they proved themselves while living, rather than being faithful throughout their life. Sumerians were constantly under attack and had to live life as if this was their last day on earth.
One of the largest cemeteries in Mesopotamia was excavated at Ur. In the late 1920s, Leonard Woolley excavated nearly two thousand burials. Of these six hundred sixty were dated to the Early Dynastic period (2900-2300 B.C.). The majority of burials were simple inhumations, in which the body, wrapped in reed matting or placed in a coffin, was set at the bottom of a rectangular pit. Clothed and accompanied by personal belongings, the deceased generally held a cup.
Sixteen burials stood apart in terms of their wealth, structure, and evidence for ritual, including human sacrifice. Woolley called these "royal tombs," assuming they contained Ur's deceased kings and queens. Without the Royal Cemetery of Ur, our knowledge of the art of the Sumerians in the middle of the third millennium B.C. A belief uncommon in many ancient religions.
Unlike even Egyptian religion, where wealth and status were determinants in the afterlife of the deceased, Sumerian kings were still bound to the same Kur as all mortals.
The burial rites of Sumerians are tied to their belief in the spirit world and they followed a strict pattern. The body was wrapped in reed matting, or occasionally placed in a coffin. The corpse was laid on its side with a bowl of water between the hands near the mouth.
Some treasured belongings might go in the grave. Vessels filled with food and water were place near the body so the spirit wouldn't be hungry and return for food. The tombs were furnished according to what the family could afford...so the royal tombs were filled with treasures.
Mesopotamian burial customs included the dead being given food and drink when buried and sometimes in monthly memorials thereafter in order to influence the gods to deal kindly with the departed. Whether this was exclusively a royal practice or not has not been determined. Further, providing food and drink was seen to give temporal blessings to the giver while he was alive.
The Sumerian religion was not a happy one. There was no shining golden afterlife, only pain and suffering in Kur. Cosmically located between the earth's crust and the primeval sea, and incredibly similar in description to the Greek Hades. It is in Kur that the first resurrection story takes place. An idea that reappears in later religions, but this account is most assuredly Sumerian.