REFN: 1590AN REFN: P1590 Gruffydd ap Llywelyn or Llewelyn Gruffydd ap Llywelyn or Llewelyn grifith äp hlwelin, looelin , d. 1063, ruler of Wales (1039-63). A series o f campaigns against other Welsh princes made him the ruler of virtually all W ales. Allied with the outlawed Ælfgar of Mercia, he launched a series of raid s into W England, but his power was broken by Harold in two invasions (1062-6 3). His defeat plunged Wales into confusion and paved the way for the conques t of Wales by the Normans. His name also appears as Griffith ap Llewelyn.