The sumerians established a form of writing known as

cuneiform

Explanation:

The Summers are officially the first civilization in the world. They were people that were much more advanced than any other group of people in their time. The Summers are responsible for developing numerous things that later were adopted by other civilizations and helped their development. Some of the things that were of great importance were the math, the basics of multiple sciences, the writing system etc. The writing system they developed is known as cuneiform, and there are lot of stone tablets on which this writing form has been preserved, providing us with lot of information about this civilization. This civilization was located in what is known as Mesopotamia, and they were the fist civilization in this area, setting up the ground for the latter civilization in this area.

where is the map if i see it i can give you the answer