Nielsen Hayden genealogy
Descendants of Lleucu ferch Llywelyn ap Gruffudd
Father: Llywelyn ap Gruffudd ap Cadwgan ap Meilir Eutun (Abt 1230 - ??)
Mother: Angharad ferch Maredudd
Lleucu ferch Llywelyn ap Gruffudd
   └─ Madog ab Iorwerth ap Madog ap Gruffudd
    Efa ferch Llywelyn ap Gruffudd
       └─ Gwerfyl ferch Madog (of Hendwr in Edeirnion, Merionethshire, Wales - Aft 1293)
        Gronwy ap Tydyr HĂȘn ap Gronwy (of Penmynydd, Anglesey, Wales - 1331 bur.Bangor, Gwynedd, Wales)
           └─ Tudur ap Gronwy ( - 1367 Trecasteil, Anglesey, Wales) =>
            + Margred ferch Thomas (of Iscoed, Ceredigion, Wales - ??)