_Sometimes_ that's a lie to give a work a greater sense of authority etc....
That said, 2100 to 1000 BC really isn't that old, "recorded history" goes back another thousand years, and civilization in Mesopotamia, if you want to count it starting with the Neolithic Revolution move to agriculture, started there around ten thousand BC. Quoting Wikipedia quoting some random from the U.K. in 2003:
"It has been identified as having 'inspired some of the most important developments in human history, including the invention of the wheel, the planting of the first cereal crops, the development of cursive script, mathematics, astronomy, and agriculture.' It is recognised as the cradle of some of the world's earliest civilizations."
As long as people have been able to talk, I'll bet elders have been saying just that sort of thing....
https://search.brave.com/search?q=oldest+know+work+of+literture
https://en.wikipedia.org/wiki/Mesopotamia