Nielsen Hayden genealogy
Descendants of Gronwy ab Owain ab Edwin
Abt 1070 -Father: Owain ab Edwin ( - 1104)
Gronwy ab Owain ab Edwin (Abt 1070 - ??)
   └─ Cristin ferch Gronwy ab Owain ab Edwin (of Tegeingl, Wales - ??)
    Owain Gwynedd, King of Gwynedd ( - 1169 bur.Bangor Cathedral, Bangor, Gwynedd, Wales)
       ├─ Angharad ferch Owain
       │ Gryffydd "Maelor" ap Madog, Prince of Northern Powys (of Powys Fadog, Wales -
       │ 1191 Castle of Dinas Bran, Nanheudwy, Wales)
       │ 1191 Castle of Dinas Bran, Nanheudwy, Wales)
       │    └─ Madog ap Gruffudd Maelor ap Madog ap Maredudd ap Bleddyn (of Powys Fadog, Wales -
       │     1236 bur.Valle Crucis Abbey, Llantysilio, Denbighshire, Wales) =>
       │     1236 bur.Valle Crucis Abbey, Llantysilio, Denbighshire, Wales) =>
       │     + Gwladus ferch Ithel ap Rhys ab Ifor ap Hywel ap Morgan Fychan ap Morgan Hir (of Gwent, Wales - ??)
       └─ Rhodri ab Owain Gwynned ( - 1195)
       
           └─ Thomas ap Rhodri ab Owain Gwynned (Abt 1170 - ??) =>
            + Margred ferch Einion ap Seisyll