Mor inherited the central and southern areas of Northern Britain around the old capital of Ebrauc (York) from his father, King Ceneu of the North, around the mid to late 5th century. Upon his own death, his vast kingdom was inherited by his son, Arthuis. A second son, Einion, became the father of Rhun Ryfedd Fawr and grandfather of Princess Perfawr, wife of King Rhun Hir of Gwynedd.