Babylonia was a state in Mesopotamia a long time ago. It was named for the capital city, Babylon, which meant The Gate of the Gods. Mesopotamia included Sumer, Akkad, and Assyria. It is important because it was one of the first places where humans lived together in a civilization. The people of Babylonia, or Babylonians, had a written language that they used to learn things about the world around them. They were actually the first people to write from left to right, and made many written documents.