Cordelia ruled peacefully for five years until her sisters' sons, Cunedagius and Marganus, came of age. As the dukes of Cornwall and Albany, respectively, they despised the rule of a woman when they claimed proper descent to rule. They raised armies and fought against Cordelia, who fought in person at numerous battles. She was captured and imprisoned by her nephews. In her grief, she committed suicide. Cunedagius succeeded her in the kingship of Britain in the lands southwest of the Humber. Marganus ruled the region northeast of the Humber. Civil war broke out between them soon after, with Marganus' being defeated and killed.