Nielsen Hayden genealogy
Descendants of Madog ap Cadwgon ap Bleddyn ap Cynfyn
Father: Cadwgon ap Bleddyn ap Cynfyn ( - 1111)
Mother: Gwenllian ferch Gruffudd
Madog ap Cadwgon ap Bleddyn ap Cynfyn
   └─ Cadwgon ap Madog ap Cadwgon ap Bleddyn
    Gwenllian ferch Owain Gwynedd
       └─ Madog ap Cadwgon ap Madog ap Cadwgon (Abt 1170 of Nannau, Meirionnydd, Wales - ??)
        Efa ferch Madog ap Philip ab Uchtrud
            + Einion ap Seisyll (Abt 1170 - ??)