Nielsen Hayden genealogy
Descendants of Iwerydd ferch Cynfyn
Father: Cynfyn ap Gwerystan (Abt 1000 - ??)
Iwerydd ferch Cynfyn
Edwin of Tegeingl ( - 1073)
   ├─ Owain ab Edwin ( - 1104)
   │ (Unknown daughter of Ednywain Bendew)
   │    ├─ Angharad ferch Owain ( - 1162)
   │    │ Gruffydd ap Cynan ab Iago, King of Gwynedd (Abt 1055 - 1137)(m. Abt 1095)
   │    │    ├─ Owain Gwynedd, King of Gwynedd ( - 1169 bur.Bangor Cathedral, Bangor, Gwynedd, Wales) =>
   │    │    │ + Gwladus ferch Llywarch
   │    │    │ + Cristin ferch Gronwy ab Owain ab Edwin (of Tegeingl, Wales - ??)
   │    │    │ + (Unknown mistress of Owain Gwynedd)
   │    │    │ + Madog ap Maredudd, Prince of Powys Fadog ( - 1160 Winchester, Hampshire, England)
   │    │    │ + Gruffydd ap Rhys (Abt 1090 - 1137)
   │    │    └─ Cadwaladr ap Gruffudd ap Cynan, King in Wales ( - 1172 bur.Bangor Cathedral, Bangor, Gwynedd,
   │    │     Wales) =>
   │    │     Wales) =>
   │    │     + Aliz de Clara (m. Bef 1151)
   │    ├─ Aldud ab Owain ab Edwin
   │    │
   │    │    └─ Owain ab Aldud ab Owain ab Edwin (Abt 1100 of Holywell, Flintshire, Wales - ??) =>
   │    │     +
   │    └─ Gronwy ab Owain ab Edwin (Abt 1070 - ??)
   │     Genilles ferch Hoedlyw ab Ithel an Edryd ab Inethan ab Iasedd ap Carwed ap Marchudd ap Cynan
   │        └─ Cristin ferch Gronwy ab Owain ab Edwin (of Tegeingl, Wales - ??) =>
   │         + Owain Gwynedd, King of Gwynedd ( - 1169 bur.Bangor Cathedral, Bangor, Gwynedd, Wales)
   └─ Uchdrud ab Edwin ap Gronwy (Abt 1030 - ??)
   
       └─ Maredudd ab Uchtrud ab Edwin ap Gronwy (Abt 1100 - ??)
        Jonet ferch Ithel ab Einudd
           └─ Hen Ithel Gam ap Maredudd ab Uchtrud ab Edwin (Abt 1130 - ??) =>
            +