 He received the lordship of Caerleon in 1031 and strengthened its fortifications.Already king of part of Morgannwg, Gruffydd became involved with Deheubarth when that kingdom was taken over from Hywel ab Edwin by Gruffydd ap Llywelyn, already king of Gwynedd, in 1044.Gruffydd ap Rhydderch was however able to expel him in 1045 and became king of Deheubarth himself.