Nielsen Hayden genealogy
Descendants of Maredudd ap Owain
- 999Father: Owain ap Hywel Dda, King of Deheubarth ( - 988)
Maredudd ap Owain ( - 999)
   └─ Angharad ferch Maredudd
    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
    :   │ (Unknown fourth wife of Bleddyn ap Cynfyn)
    :   │ :    + Gwenllian ferch Gruffudd
    :   │ :    + (Unknown wife or mistress of Cadwgon ap Bleddyn)
    :   │ (Unknown wife of Bleddyn ap Cynfyn)
    :   │     + Llywelyn Eurdorchog ap Coel ap Gweirydd (Abt 1030 - ??)
    :   └─ Rhiwallon ap Cynfyn (Abt 1020 - Abt 1069)
    :   
    :        + Rhys ap Tewdyr, King of Deheubarth ( - Apr 1093 Brycheiniog, Wales)
    Llywelyn ap Seisyll, King of Deheubarth (Abt 980 - 1023)(m. 994)
       └─ Gruffydd ap Llywelyn, King of Wales ( - 5 Aug 1064 Ireland)
        Ealdgyth of Mercia, Queen Consort of England ( - Aft 1066)(m. Abt 1057)
           └─ Nest ferch Gruffydd (Between 1055 and 1057 - ??) =>
            + Osbern fitz Richard (of Richard's Castle, Herefordshire, England - Aft 1086)