Nielsen Hayden genealogy
Descendants of Merfyn Frych ap Gwriad, King of Gwynedd
- 844Father: Gwriad (of the Isle of Man - ??)
Mother: Esyllt ferch Cynan Dindaethwy
Merfyn Frych ap Gwriad, King of Gwynedd ( - 844)
   └─ Rhodri Mawr, King of Gwynedd ( - 878)
   
       ├─ Anarawd ap Rhodri Mawr, King of Gwynedd
       │
       │    └─ Idwal Voel ab Anarawd, King of Gwynedd (Abt 880 - 943) =>
       │     +
       └─ Cadell ap Rhodri, King of South Wales ( - 910)
       
           └─ Hywell Dda ap Cadell, King of South Wales (Abt 875 - 950) =>
            + Elen ferch Llywarch ( - 929)