Sumer was the site of the earliest known civilization, and was located in the southern part of Mesopotamia between the Tigris and Euphrates rivers. It was in the area that later became Babylonia and is now southern Iraq. This civilization was around mainly during the Chalcolithic and the Early Bronze ages. Although the earliest examples of writing in the region do not go back much further than 2500 BC, current historians have suggested that Sumer was first permanently settled between 5500 and 4000 BC by a non-Semitic people who spoke the Sumerian language (pointing to the names of cities, rivers, basic occupations, etc., as evidence). These prehistoric people are now called "proto-Euphrateans" or "Ubaidians", and are theorized to have evolved
