The Sumerians were the first group of people to live in Mesopotamia. They settled in the region between the Tigris and Euphrates rivers in what is now Iraq around 3500 BC. The Sumerians were a highly advanced civilization, and they are credited with developing the world's first cities, the first writing system, and the first schools. They also made important advances in mathematics, astronomy, and architecture. The Sumerians were conquered by the Akkadians in 2334 BC, but their culture continued to influence the development of Mesopotamian civilization for centuries to come.