During the later period of the Empire, the name "Flavius" frequently descended from one emperor to another, beginning with Constantius, the father of Constantine the Great. The name became so ubiquitous that it was sometimes treated as a praenomen, to the extent of being regularly abbreviated "Fl.", and it is even described as a praenomen in some sources, although it was never truly used as a personal name. The last emperor to take the name was eastern emperor Constantine IV, during the seventh century.