This is from Peter Bartrum's Welsh Genealogies AD 300-1500 and I have adjusted the dates from the records in the Book of Llandaff and elsewhere. I did deviate from Bartrum in line B, because the Book of Llandaff and the sources mentioned by Bartrum in A Welsh Classical Dictionary seem to suggest there were two Meurigs whose mothers were named Enynny. Corrections and critiques are not only welcomed, but desired. Sources following.
A1. Erb, King of Gwent (c. 475-aft. c. 555)
A2. Nynnio, King of Gwent (b. c. 505)
A3. Llywarch, King of Gwent (b. c. 535)
A4. St. Tewdrig, King of Gwent (c. 565-c. 625) m. Enynny (b. c. 570) (same as B4)
A5. Meurig, King of Gwent and Glywysing (c. 590-c. 665) m. Onbrawst (b. c. 595)
A6. Athrwys, King of Ergyng (c. 615-bef. c. 665) m. Cendlen (b. c. 620)
A7. Morgan, King of Gwent and Glywysing (c. 645-c. 710) m. Rhiceneth
A8. Iudhael, King of Gwent (c. 680-c. 745)
A9. Rhys, joint-king of Glywysing (c. 720-c. 775) m. Ceingar (b. c. 750)
A10. Arthfael, King of Glywysing (b. c. 765) m. Brawstudd (b. c. 775)
A11. Rhys (b. c. 795)
A12. Hywel, King of Glywysing (c. 830-c. 886) m. Lleucu
A13. Owain, King of Glywysing and Gwent (c. 860-c. 930) m. Nest ferch Rhodri Mawr
A14. Morgan "Hen", King of Morgannwg (ca. 890-974)
A15. Idwallon, joint-king of Morgannwg (b. c. 935)
A16. Ithel (b. c. 970)
A17. Gwrgan (b. c. 1010)
A18. Iestyn, King of Morgannwg (c. 1040-1093)
A19. Madog, Lord of Rhuthian (b. c. 1080) m. Jonet ferch Ynyr Fychan ap Meurig
A20. Hywel, Lord of Meisgyn (b. c. 1115) m. Mawd ferch Gruffudd ab Ifor Bach
A21. Cynwrig, Lord of Radur (b. c. 1155) m. Angharad ferch Lewys ap Rhys
A22. Hywel, Lord of Radur (b. c. 1190)
A23. Meurig, Lord of Llanharan (b. c. 1230) m. Crisli ferch Adam Fychan ab Adam
A24. Dafydd (b. c. 1265) m. Efa ferch Hopkin ap Hywel Fychan
A25. Glawdus (b. c. 1305) m. Ieuan ap Rhys ab Ifor Goch
A26. Mawd (b. c. 1330) m. Llywelyn ap Hywel Fychan ap Hywel
A27. Sir Dafydd Gam (c. 1355-1415) m. Gwenllian ferch Gwilym ap Hywel Grach
A28. Gwladys "the Star of Abergavenny" (c. 1388-1454) m Sir William ap Thomas (d. 1446)
A29. William Herbert, 1st Earl of Pembroke (ca. 1423-1469) m. Anne Devereux
A30. Lady Katherine Herbert (c. 1468- bef. 1503) m. George Grey, 2nd Earl of Kent (c. 1443-1503)
A31. Lady Anne Grey (c. 1492-1546) m. John Hussey, Baron Hussey of Sleaford (1465-1537)
A32. Elizabeth Hussey (c. 1512-1554) m. Sir Robert Throckmorton, of Coughton (d. 1581)
A33. Muriel Throckmorton (d. 1615) m. Sir Thomas Tresham, of Rushton Hall (1543-1605)
A34. Mary Tresham (c. 1585-1664) m. Thomas Brudenell, 1st Earl of Cardigan (ca. 1583-1663)
A35. Robert Brudenell, 2nd Earl of Cardigan (1607-1703) m. Lady Anne Savage
A36. Francis Brudenell, Lord Brudenell (1654-1698) m. Lady Frances Savile (d. 1695)
A37. Anne Brunedell (1671-1722) m. Charles Lennox, 1st Duke of Richmond (1672-1723)
B1. Glywys, King of Glywysing (b. c. 450)
B2. Dyfwn (b. c. 520) m. Meurig, King of Glywysing (b. c. 520), a son of Caradoc and Enynny
B3. Erbic, King of Glywysing (b. c. 545)
B4. Enynny (b. c. 570) m. St. Tewdrig, King of Gwent (c. 565-c. 625)
B5. (same as A5) Meurig, King of Gwent and Glywysing (c. 590-c. 665)
C1. Eudaf Hen
C2. Gadeon
C3. Morfawr/Gwrfawr
C4. Tudwal
C5. Cynfor
C6. Custennin Gorneu
C7. Erbin
C8. Geraint (c. 465-c. 510) m. Gwyar ferch Amlawd Wledig
C9. Cadwy (Cado/Cador of Arthurian lore) (c. 490-c. 537)
C10. Peredur (? = Berth ap Cado of Arthurian lore) (b. c. 520)
C11. Theudu (b. c. 560)
C12. (?) ? (b. c. 595) m. Briafel Frydic ap Llywarch ap Tewdwr ap Peibo Glafoeriog ap Erb
C13. Cendlen (b. c. 620) m. Athrwys, King of Ergyng (c. 615-bef. c. 665)
C14. (same as A7) Morgan, King of Gwent and Glywysing (c. 645-c. 710)
D1. Emperor Magnus Maximus (c. 335-388) (? m. Helen)
D2. Severa m. Vortigern, King of Britain (c. 370-c. 441)
D3. Pascent, King of Buellt and Gwrtheyrnion (b. c. 410)
D4. Riagath, King of Buellt and Gwrtheyrnion (b. c. 445)
D5. Mepurit, King of Buellt and Gwrtheyrnion (b. c. 485)
D6. Paul, King of Buellt and Gwrtheyrnion (b. c. 520)
D7. Eldoc, King of Buellt and Gwrtheyrnion (b. c. 555)
D8. Eldad, King of Buellt and Gwrtheyrnion (b. c. 590)
D9. Moriud, King of Buellt and Gwrtheyrnion (b. c. 625)
D10. Guoidcant, King of Buellt and Gwrtheyrnion (b. c. 660)
D11. Pascent, King of Buellt and Gwrtheyrnion (b. c. 700)
D12. Gloud (b. c. 735)
D13. Brawstudd (b. c. 775) m. Arthfael, King of Glywysing (b. c. 765)
D14. (same A11) Rhys (b. c. 795)
Sources
Peter Bartrum, Welsh Genealogies AD 300-1500
http://cadair.aber.ac.uk/dspace/handle/2160/4026
Peter Bartrum, A Welsh Classical Dictionary: People in History and Legend up to about A.D. 1000
http://www.llgc.org.uk/collections/digital-gallery/printedmaterial/a-welsh-classical-dictionary/
Wendy Davies, An Early Welsh Microcosm: Studies in the Llandaff Charters (London, 1978)
Wendy Davies, The Llandaff Charters (Aberystwyth, 1979)
William Addams Reitwiesner, The Ancestors of Rev. Roger Parry, Rector of Hinton-Ampner (d. 1634)
http://www.wargs.com/family/parry.html
Vortigern Studies
http://www.vortigernstudies.org.uk/questhomepage.htm
Historia Brittonum (828)
http://www.vortigernstudies.org.uk/arthist/vortigernquoteshb.htm
http://www.yorku.ca/inpar/nennius_giles.pdf