38And he began to make the ark; and whenever the chiefs from among his people passed by him they laughed at him

40Until when Our command came and water came forth from the valley, We said: "Carry in it two of all things, a pair, and your own family

We all know the story of the flood as both major texts have this story. The biblical account pre-dates the Koran, so we know that the Koran used the biblical story in their book.  However, can we say the biblical story was the first account of such an event?  We know that it is not the first account.  The flood story was an ancient story, passed down throughout history.  The oldest documented account we have of a flood story is from the Sumerians, in the flood of Gilgamesh.

Tear down the house and build a boat!

  Abandon wealth and seek living beings!

  Spurn possessions and keep alive living beings!

  Make all living beings go up into the boat

When a seventh day arrived

I sent forth a dove and released it.

The dove went off, but came back to me;

no perch was visible so it circled back to me.

I sent forth a swallow and released it.

The swallow went off, but came back to me;

no perch was visible so it circled back to me.

I sent forth a raven and released it.

The raven went off, and saw the waters slither back.

It eats, it scratches, it bobs, but does not circle back to me.

 We all know the story as depicted in the Bible and Koran, Noah and his family are the sole survivors of this flood, and they repopulate the earth.  However, the Greeks, although they spoke of an ancient deluge, had a different take on this story.  The Greeks version pre-dated the bible, and makes no mention of Noah.    In Plato’s laws, there was dialogue referring to this very subject.

Ath. Do you believe that there is any truth in ancient traditions?
Cle. What traditions? 
Ath. The traditions about the many destructions of mankind which have been occasioned by deluges and pestilences, and in many other ways, and of the survival of a remnant? 

Cle. Every one is disposed to believe them. 
Ath. Let us consider one of them, that which was caused by the famous deluge. 

Cle. What are we to observe about it? 
Ath.hill shepherds-small sparks of the human race preserved on the tops of mountains. 

Cle. Clearly. 
Ath. Such survivors would necessarily be unacquainted with the arts and the various devices which are suggested to the dwellers in cities by interest or ambition, and with all the wrongs which they contrive against one another. 

Cle. Very true. 
Ath. Let us suppose, then, that the cities in the plain and on the sea-coast were utterly destroyed at that time. 

Cle. Very good. 
Ath. Would not all implements have then perished and every other excellent invention of political or any other sort of wisdom have utterly disappeared? 

It is very easy to summarize that the story of the flood, originating in Sumerian storytelling, made its way by word of mouth to other cultures throughout the centuries, where the Greeks discussed it without reference to Noah.  It is obvious that the story of Noah was not formed before the Greeks. Although Plato's writings were after the Genesis version, his version was passed down from before Genesis.   They spoke of a flood occurring and mentioned the fact that there had to be numerous survivors. The book of Genesis added the story of Noah in as an addition to the common flood stories that originated from the Sumerians 2000 years before. This is why Plato makes no mention of Noah in his dialogues.   When Mohammed was spreading Islam centuries after the bible was written, it was added into the Koran.   

This very small history of the great flood can only show that it was a myth spread out and used by numerous religions.  History can be a fantastic tool, if understood, to use with theists.