The well-known Sumerian King List dates to the early second millennium BC. It consists of a succession of royal dynasties from different Sumerian cities, ranging back into the Early Dynastic Period. Each dynasty rises to prominence and dominates the region, only to be replaced by the next. The document was used by later Mesopotamian kings to legitimize their rule. While some of the information in the list can be checked against other texts such as economic documents, much of it is probably purely fictional, and its use as a historical document is limited.