The Sumerians were the very first people to settle into Mesopotamia (modern-day Iraq) around 4800 BC marking the emergence of the first human civilization. Gifted and imaginative, they developed the first known system of writing. The Sumerian language, linguistically separate from any other, has been preserved for us today through the thousands of clay tablets its speakers left behind. Sumerians also invented the wheel, a mathematical system based on the number 60 (the basis of time in the modern world), and a system of banking.