Nielsen Hayden genealogy
Descendants of Cynfyn ap Gwerystan
Abt 1000 -Father: Gwerystan (Abt 955 - ??)
Cynfyn ap Gwerystan (Abt 1000 - ??)
:   ├─ Bleddyn ap Cynfyn, King of Gwynedd & Powys ( - 1075)
:   │ Haer ferch Cillin
:   │ :   └─ Maredudd ap Bleddyn ap Cynfyn (of Powys, Wales - 1132)
:   │ :    Hunydd ferch Einudd
:   │ :       ├─ Madog ap Maredudd, Prince of Powys Fadog ( - 1160 Winchester, Hampshire, England) =>
:   │ :       │ + Susanna ferch Gruffydd ap Cynan
:   │ :       │ + (Unknown wife or mistress of Madog ap Maredudd)
:   │ :        + Gwerful ferch Gwrgeneu
:   │ (Unknown fourth wife of Bleddyn ap Cynfyn)
:   │ :   └─ Cadwgon ap Bleddyn ap Cynfyn ( - 1111)
:   │ :    Gwenllian ferch Gruffudd
:   │ :    :    + Jane ferch Cynwrig
:   │ :    (Unknown wife or mistress of Cadwgon ap Bleddyn)
:   │ :       └─ Owain ap Cadwgon ( - 1116)
:   │ :        + Nest ferch Rhys (Abt 1085 - Bef 1136)
:   │ (Unknown wife of Bleddyn ap Cynfyn)
:   │    └─ Efa ferch Bleddyn ap Cynfyn
:   │     Llywelyn Eurdorchog ap Coel ap Gweirydd (Abt 1030 - ??)
:   │         +
:   └─ Rhiwallon ap Cynfyn (Abt 1020 - Abt 1069)
:   
:       └─ Gwladus ferch Rhiwallon
:        Rhys ap Tewdyr, King of Deheubarth ( - Apr 1093 Brycheiniog, Wales)
:            + Henry I, King of England (1068 - 1 Dec 1135 Lyon-la-ForĂȘt, near Rouen, Seine-Maritime, Normandy,
:            : France)
:            : France)
:            + Gerald of Windsor (1070 - Aft 1116)
:            + Owain ap Cadwgon ( - 1116)
   └─ Iwerydd ferch Cynfyn
    Edwin of Tegeingl ( - 1073)
       ├─ Owain ab Edwin ( - 1104)
       │ (Unknown daughter of Ednywain Bendew)
       │    │ + Gruffydd ap Cynan ab Iago, King of Gwynedd (Abt 1055 - 1137)(m. Abt 1095)
       │    │ +
       │     + Genilles ferch Hoedlyw ab Ithel an Edryd ab Inethan ab Iasedd ap Carwed ap Marchudd ap Cynan
       └─ Uchdrud ab Edwin ap Gronwy (Abt 1030 - ??)
       
           └─ Maredudd ab Uchtrud ab Edwin ap Gronwy (Abt 1100 - ??) =>
            + Jonet ferch Ithel ab Einudd