The "Sumerian" civilization is credited with the invention of writing... but did you know they are also responsible for many of the stories we find in "Genesis," as well as man's first concepts of "time" and "law" ?
Little is known of the earliest Sumerians, but the hot, harsh climate of Mesopotamia would cultivate settlements that were flourishing as early as 3000 B.C. They were perhaps nomadic wanderers who made their way from the mountains into the valley regions, but little is known of their origin because they were simply unrelated to any other people or language of the time (ca. 3500 B.C.)
I always found them interesting because they give us our first glimpse of "historical" writings. They used a pictographic language and their texts were written by pressing the end of a reed or thin animal bone into wet tablets of clay. The tablets were baked, and this produced a wedge-shaped form of writing we know as "Cuneiform." It was a difficult and time-consuming, and as such, there were only a few scribes working on documents in this era.
The Sumerians had a complex government and society, despite the fact that they lived in a region of extreme heat, sweeping sandstorms, a white-hot sun, and very little rain. When the rains did come they were in the form of sudden flash-floods, and farming soil was left damp, marshy, and untendable.
What these people DID have was a very good form of trade. They were masters in metals, glass, textile-weaving, and they worked with the precious items of bronze, copper, gold, and iron. This trade brought them in touch with many different cultures -- and it's very probable their contact with the early Hebrews gave rise to many of the stories used in the Old Testament, particularly the first book of "Genesis." For example, the Sumerians were the first to have a story of the "Tree of Knowledge" and they spoke of a "Paradise" that had been lost to man. This is paralleled in the later Hebrew texts and the Biblical "Garden of Eden." The Sumerians also told a story of a "Great Flood" and the "Tower of Babylon," too, was theirs.
It is interesting that the "Great Flood" shows up in one of the earliest works of literature, the Babylonian "Epic of Gilgamesh." I have not read this (someday I will find time!) but it is based on a series of older Sumerian stories about the mythical king "Aggas" of Kish.
The Sumerians also provided the earliest concepts of "divine law" and a "divine justice." It can be argued that the Hebrews, likewise, developed a strong sense of these two elements in their religion -- although they focused on one "God" while the Sumerians had many different gods.
We also take our notion of the "foot" having 12 inches from them.
And the fact that minutes and hours each have units of "60."
And also that a "Day" has 24 hours.