Magnus Maximus
Welsh kings would later use the authority of Magnus Maximus as the basis of their inherited political legitimacy. While imperial Roman entries in Welsh royal genealogies lack any historical foundation, they serve to illustrate the belief that legitimate royal authority began with Magnus Maximus. As told in "The Dream of Emperor Maximus", Maximus married a Briton, and their supposed children are given in genealogies as the ancestors of kings. Tracing ancestries back further, Roman emperors are listed as the sons of earlier Roman emperors, thus incorporating many famous Romans (e.g., Constantine the Great) into the royal genealogies.