Sumer, nowadays referred to as Iraq, is an ancient civilization that existed in Mesopotamia from around 4500 BC to 1750 BC. It was one of the first civilizations in the world and is considered to be the cradle of civilization. Sumerians developed a writing system, invented the wheel, and created the first known legal code. They also developed irrigation systems and built large cities. Sumerian culture and language had a great influence on the cultures of the Middle East and beyond.