He journeys into the underworld in search of them. Upon finding them, he soon discovers how they achieved immortality and realizes it's beyond his reach. The ancient kings wife takes pity on Gilgamesh and offers him one final method that may work. Again, Gilgamesh fails and returns to the city of Uruk. .
The Epic of Gilgamesh is thought to have begun as an oral tradition before the story was finally recorded. The innovation of written language in the form of Cuneiform made it possible for the story to finally be recorded. As with all oral traditions, myths and stories often change from telling to telling. We therefore should assume that at the time of it's recording, the epic had evolved into a snapshot of the personal biases, beliefs and practices of the people recording the story. The many ancient tablets that bore this epic were only uncovered two hundred years ago with considerable gaps in the story. In some cases, different versions of the story could be compared as time passed. We know that Sumerian city-states were especially vulnerable to invasion do to the geography of the region. To compensate, many cities built massive defensive walls to protect themselves. King Gilgamesh of Uruk seems to confirm this as he directs his people to build a wall around the city. Also represented is the movement of humanity from a mobile, hunter/gatherer society to a sedentary, agricultural one. In the story, Gilgamesh is portrayed as semi-divine. This may be a result of religious centers being established as cities formed. Because Mesopotamians saw cities as a copy of a divine model, then its leader and creator must be in some way divine as well, as Gilgamesh was.
The religious beliefs of the Mesopotamian people were expressed in The Epic of Gilgamesh in a variety of ways. A polytheistic system must have been in place due to the mention of several gods in the story. The supernatural intervened in human affairs all through the story, from the creation of Enkidu to Gilgamesh's disappointment in the netherworld.