 The "Frithfolad Muman" text states that the Osraige had once been kings of Munster and makes it clear that they were a privileged and powerful group, but no longer a major force, "the respectable has-beens of Munster politics".The period of Cerball's life covered much of the first Viking Age, and he is notably mentioned in later Nordic sources.The Icelandic Landnámabók describes Cearbhall ("Kjarvalur") as ruler of Dublin and Earl of Orkney and opens with a list of the most prominent rulers in Viking-age Europe, listing this Ossorian king alongside other well-known rulers of that era, specifically Popes Adrian II and John VIII; Byzantine Emperors Leo VI the Wise and his brother Alexander; Harald Fairhair, king of Norway; Eric Anundsson and his son Björn Eriksson rulers of Sweden; Gorm the Old, king of Denmark; and Alfred the Great, king of England.