linguistic:paraphrasing, information:classification
Mesopotamian

The Noah story of the Pentateuch is quite similar to a flood story contained in the Mesopotamian Epic of Gilgamesh, composed c. 1800 BCE. In the Gilgamesh version, the Mesopotamian gods decide to send a great flood to destroy mankind. Various correlations between the stories of Noah and Gilgamesh (the flood, the construction of the ark, the salvation of animals, and the release of birds following the flood) have led to this story being seen as the source for the story of Noah. The few variations include the number of days of the deluge, the order of the birds, and the name of the mountain on which the ark rests. The flood story in Genesis 6–8 matches the Gilgamesh flood myth so closely that "few doubt that derives from a Mesopotamian account." What is particularly noticeable is the way the Genesis flood story follows the Gilgamesh flood tale "point by point and in the same order", even when the story permits other alternatives.

The earliest written flood myth is found in the Mesopotamian Epic of Atrahasis and Epic of Gilgamesh texts. The Encyclopædia Britannica says "These mythologies are the source of such features of the biblical Flood story as the building and provisioning of the ark, its flotation, and the subsidence of the waters, as well as the part played by the human protagonist." The Encyclopedia Judaica adds that there is a strong suggestion that "an intermediate agent was active. The people most likely to have fulfilled this role are the Hurrians, whose territory included the city of Harran, where the Patriarch Abraham had his roots. The Hurrians inherited the Flood story from Babylonia". The encyclopedia mentions another similarity between the stories: Noah is the tenth patriarch and Berossus notes that "the hero of the great flood was Babylonia's tenth antediluvian king." However, there is a discrepancy in the ages of the heroes. For the Mesopotamian antecedents, "the reigns of the antediluvian kings range from 18,600 to nearly 65,000 years." In the Bible, the lifespans "fall far short of the briefest reign mentioned in the related Mesopotamian texts." Also, the name of the hero differs between the traditions: "The earliest Mesopotamian flood account, written in the Sumerian language, calls the deluge hero Ziusudra."

However, Yi Samuel Chen writes that the oldest versions of the Epic of Gilgamesh never mentioned the flood, just mentioning that he went to talk to Utnapishtim to find the secret of immortality. Starting with the Old Babylonian Period, there were attempts to syncretize Utnapishtim with Ziusudra, even though they were previously seen as different figures. Gilgamesh meeting the flood hero was first alluded to in the Old Babylonian Period in "The Death of Gilgamesh" and eventually was imported and standardized in the Epic of Gilgamesh probably in the Middle Babylonian Period.

Gilgamesh 's historical reign is believed to have been approximately 2700 BC, shortly before the earliest known written stories. The discovery of artifacts associated with Aga and Enmebaragesi of Kish, two other kings named in the stories, has lent credibility to the historical existence of Gilgamesh.

The earliest Sumerian Gilgamesh poems date from as early as the Third dynasty of Ur (2100–2000 BC). One of these poems mentions Gilgamesh’s journey to meet the flood hero, as well as a short version of the flood story, although Chen writes that his was included in texts written during the Old Babylonian Period. The earliest Akkadian versions of the unified epic are dated to c. 2000–1700 BC. Due to the fragmentary nature of these Old Babylonian versions, it is unclear whether they included an expanded account of the flood myth; although one fragment definitely includes the story of Gilgamesh’s journey to meet Utnapishtim. The "standard" Akkadian version included a long version of the flood story and was edited by Sin-liqe-unninni sometime between 1300 and 1000 BC.

Yi Samuel Chen, analyzing various texts from the Early Dynastic III Period to the Old Babylonian Period, argues that the flood narrative was only added in texts written during the latter Old Babylonian Period. Observations by experts indicate that the portions of the Sumerian King List which mention the time before the flood are stylistically different from the King List Proper. Chen writes that Old Babylonian copies tend to show a separate pre-flood tradition which is apart from the King List. Further, the Ur III copy of the King List as well as similar documents indicate that the King List Proper once existed independent of a flood narrative or a pre-flood tradition. Chen provides evidence that the sections of the Sumerian King List that mention references to the flood were all later additions added during the Old Babylonian Period through later updates and edits. The Flood as a watershed in early history of the world was probably a new historiographical concept emerging in the Mesopotamian literary traditions during the Old Babylonian Period, as evident by the fact that the flood motif didn't show up in the Ur III copy and that the earliest chronographical sources related to the flood show up in the Old Babylonian Period. Chen concludes that the name of Ziusudra as a flood hero, as well as any hinted references of a flood, in the Old Babylonian Version of the Instructions of Shuruppak were later developments during the Old Babylonian Period, originating from updated information added to the text from the burgeoning Antediluvian Tradition.