When the civilization of Sumer was already a thousand years old, around 2300 BC, we find written accounts of creation, a primitive paradise, and a flood that destroyed the world:
After Anu, Enlil, Enki, and Ninhursag
had fashioned the black-headed people,
Vegetation sprang from the earth,
Animals, four-legged creatures of the plain,
Were brought artfully into existence
[37 lines are unreadable]
After the....of kingship had been lowered from heaven
After the exalted crown and the throne of kingship
Had been lowered from heaven,
He perfected the rites and exalted the divine ordinances...
He founded the five cities in pure places,...
Then did Nintu weep like a....
The pure Inanna set up a lament for its people,
Enki took council with himself,
Anu, Enlil, Enki, and Ninhursag....
The gods of heaven and earth uttered the name of Anu and Enlil
Then did Ziusudra, the king, the priest of...,
Build a giant...;
Humbly obedient, reverently he...
Attending daily, constantly he...,
Bringing forth all kinds of dreams, he...,
Uttering the name of heaven and earth, he...[...]
the gods a wall...,
Ziusudra, standing at its side, listened.
"Stand by the wall at my left side...,
By the wall I will say a word to you,
Take my word,
Give ear to my instructions:
By our...a flood will sweep over the cult-centers;
To destroy the seed of mankind...,
Is the decision, the word of the assembly of the gods.
By the word commanded by Anu and Enlil...,
Its kingship, its rule will be put to an end.
[about 40 lines missing]
All the windstorms, exceedingly powerful,
Attacked as one,
At the same time, the flood sweeps over the cult-centers.
After, for seven days,
the flood sweeps over the cult centers.
After, for seven days and seven nights,
The flood had swept over the land,
And the huge boat had been tossed
About by the windstorms on the great waters,
Utu came forth, who sheds light on heaven and earth,
Ziusudra opened a window of the huge boat,
The hero Utu brought his rays into the giant boat.
Ziusudra, the king,
Prostrated himself before Utu
Gilgamesh became the hero of the Babylonian epic poem which bears his name, and which also contains an account of the flood. Until recently, these king lists and the names in them were thought to be purely fanciful. But in the 1930's, Sir Leonard Woolley, while excavating a building at Ur on the Ubaid level, found an inscription indicating that the structure had been erected by the son of the founder of the First Dynasty of Ur, a person up till that time regarded as fiction.
Gilgamesh, too, has been found to be a real person, with inscriptions telling of the buildings he built.
Sumerian Legend of Creation
ENUMA ELISH
http://history-world.org/sumerian_legend_of_creation.htm