A wedge-shaped script invented in southern Mesopotamia in the second half of the 4th millennium BCE. It was primarily written on clay tablets. The signs were impressed in the wet clay with a (reed) stylus. Several languages were written in cuneiform, most notably Sumerian and Akkadian, including the Assyrian and Babylonian dialects. The latest clay tablet with cuneiform writing on it dates to the 1st century CE.