The names of those known to have ruled over one or more of the principalities are listed below (those in heavy type ruled over a large portion of Wales)
Morgan the Old (Morgan Hen or Morgan ab Owain) (930-974) united the former kingdoms of Gwent and Glywysing in 942 under the name of Morgannwg, but they were broken up again immediately after his death, remaining separate until about 1055
Glywysing
Morgan the Old's son, Owain ap Morgan (974-about 983)
brothers of Owain ap Morgan (dates unknown)
his son, Rhys ab Owain (about 990-about 1000) who ruled Glywysing jointly with his brothers,
Hywel ab Owain (about 990-about 1043) and
Iestyn ab Owain (about 990-about 1015)
his brother, Rhydderch ap Iestyn (about 1015-1033)
his son, Gruffydd ap Rhydderch (1033-1055)
Gwent
Nowy ap Gwriad ruled Gwent (about 950-about 970) while Glywysing was ruled jointly by brothers of Owain ap Morgan (dates unknown)
his son, Arthfael ap Nowy (about 970-983)
his cousin, Rhodri ap Elisedd (983-about 1015) who ruled jointly with his brother,
Gruffydd ap Elisedd (983-about 1015)
his ?cousin, Edwyn ap Gwriad (1015-1045)
Hywel ab Owain's son, Meurig ap Hywel (1045-1055) who ruled jointly with
his son, Cadwgan ap Meurig (1045-1074) who for a time ruled jointly with
Gruffydd ap Rhydderch's son, Caradog ap Gruffydd (1063-1081)
Iestyn ap Gwrgan(t) (1081-1091)
Iestyn was the last ruler of an independent Morgannwg, which was thereafter in the possession of the Normans and was re-named Glamorgan
Powys
Rhodri the Greattook Powys within the principality of Gwynedd, where it remained until 1075
Bleddyn ap Cynfyn's son, Madog ap Bleddyn (1075-1088)
his brother, Iorwerth ap Bleddyn (1088-1103) who ruled jointly with
his brother, Cadwgan ap Bleddyn (1088-1111)
his son, Owain ap Cadwgan (1111-1116)
his uncle, Maredudd ap Bleddyn (1116-1132)
his son, Madog ap Maredudd (1132-1160)
his son, Gruffydd Maelor (1160-1191) who ruled Northern Powys only
his son, Owain ap Gruffydd Maelor (1191-1197) who ruled Northern Powys jointly with
his brother, Madog ap Gruffydd Maelor (1191-1236)
his son, Gruffydd Maelor ap Madog (1236-1269)
Southern Powys was ruled by
Madog ap Maredudd's nephew, Owain Cyfeiliog (1160-1195)