The pedigrees in the first table relate to Tewdrig, king of Gwent, of gen. 1. As stated in JC 9, he was the son of Llywarch. In two later documents, ABT 15a and MP 3b of the 15th and 16th C respectively, he is mistakenly given a father named Teithfall , a conflation with the Tewdrig of the second table below. The Liber Landavensis tells of his martyrdom. It was foretold that following his victory over the Saxons there would be peace for 30 years. The renewed conflict is referred to in the ASC under the year 577. The LL also mentions Teilo receiving gifts from him.

Gen. ABT 15a HG 28 HG 29 JC 9 seg.
JC 10a MP 3a
MP 3b seg.
19 Morgan
18 Caradog Caradog
17 Iestyn Iestyn
16 Gwrgan Gwrgan
15 Ithel Ithel
14 Idwallon Idwallon
13 Morgan Mawr Morgan Hen Morgan Hen Morgan (Mwyn)fawr [Hen]
12 Owain Owain Owain Owain
11 Hywel Brochwel Hywel Hywel Hywel
10 Rhys Meurig Rhys Rhys Rhys Meurig
9 Arthfael Ithel Arthfael Arthfael Arthfael Arthfael Arthfael
8 [Gwriad] Athrwys [Gwriad] Gwriad Cenedlon Gwriad [Gwriad]
7 [Brochwel] Ffernfael [Brochwel] Brochwel Briafael Frydig Brochwel [Brochwel]
6 Rhys Ithel Rhys Rhys Llywarch Rhys
5 (Ithel) [Einudd] [Einudd] (Ithel) [Einudd] [Ei]Nudd (Hael) Tewdwr Einudd
4 Morgan Morgan Morgan Morgan [Angwarad] Morgan
3 Athrwys Athrwys Athrwys Peibio Glafrog Athrwys
2 Meurig [Meurig] Meurig Arbeth Meurig
1 Tewdrig Tewdrig Tewdrig Dyfrig St. Tewdrig
0 (Teithfall) [Llywarch] Llywarch [Efrddyl] (Teithfall) [Llywarch]
-1 Nynnio Nynnio Peibio Nynnio
-2 Erb Erb Erb
-3 Erbic Erbic Erbic
-4 Meurig Meurig
-5 Enynny Enynny

The table is in accordance with the following data:
St. Dyrfrig died 612.
Morgan ab Athrwys died 665.
Ffernfael ab Ithel died 775.
Ithel ab Athrwys died 848.
Meurig ab Arthfael (brother of Rhys) died 874.
Hywel ap Rhys died 886.

Owain ap Hywel submitted to Æthelstan according to ASC D for the year 926, which refers to him as “Uwen Wenta cyning”. He was a contemporary of Bishop Cyfeiliog who the LL states died in 927. The bishop is also mentioned in the ASC A under the year 914.
Morgan Hen died 974 and contemporary of King Edgar. His mother was probably Nest ferch Rhodri Mawr.

HG 28 gives the pedigree for the rulers of Glywysing whereas HG 29 gives that for Gwent. This is confirmed by Asser 80. Note, HG 29a and ABT 15a incorrectly name, in gen. 5, Ithel instead of Einudd as he had a son called Rhys who was confused with a son of Ithel of gen. 6, who was also called Rhys and who was a brother of Ffernfael according to LL. Later, the corruption Iudhail, which was the early form of the name Ithel,  was itself corrupted to Nudd Hael in JC 9. The pedigrees in the second table are relevant to the earlier Tewdrig ap Teithfall, king of Garthmadrun.

Gen. JC 1a
JC 1b
V. Cadoci 46a
V. Cadoci 46c
1 Cadog Cadog
0 Cynog Gwladus Gwladus
-1 Brychan Brychan Brychan [Brychan]
-2 [Anlach] Marchell Anlach Marchell
-3 Coronac Tewdrig [Coronac] Tewdrig
-4 Eurbre Wyddel Teithfall Eurbre Wyddel  Teithfall
-5 Teithrin Brusc
-6 Briscethach

Gwladus ferch Brychan was a contemporary of Arthur.

The regnal list of Glywysing

The kings of Glywysing were descended from King Arthur as indicated by JC20 12:

Gen. JC20 12a seg.
13 Morgan Hen
12 Owain
11 Hywel
10 Rhys
9 Arthfael
8 Ceingar
7 Maredudd
6 Tewdws
5 [Rhain]
4 Cadwgon
3 Cathen
2 Gwlyddien
1 Nowy
0 Arthur
-1 Pedr
-2 Cyngar

Morgan Hen died in the year 974. The LL tells us:

Morgan Hen son of Owain, King of Glamorgan, contemporary with Edgar, King of England …[1]

Edgar died a year later in 975. The father of Morgan, Owain, according to the ASC, accepted Athelstan as overlord in the year 926. Arthfael’s father is given by JC 9 as Gwriad ap Brochwel. His mother, Ceingar from Dyfed.

[1] Rees, W. J., 1840, 502