Nielsen Hayden genealogy
Descendants of Gwion Sais ap Heilin ap Llywarch ap Gwyn
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Father: Heilin ap Llywarch ap Gwyn ap Tewdwr Mawr
(Abt 1100 - ??)
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Gwion Sais ap Heilin ap Llywarch ap Gwyn (Abt 1170 - ??)
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Owain ap Gruffudd ab Yr Arglwydd Rhys
( - 18 Jan 1236 Strata Florida Abbey, Ceredigion, Wales)
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       └─ Maredudd ab Owain ap Gruffudd ab Yr Arglwydd Rhys
( - Mar 1265 Llanbardarn Fawr, Ceredigion, Wales)
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           └─ Owain ap Maredudd ab Owain ap Gruffudd
(of Iscoed, Ceredigion, Wales -
            15 Aug 1275 bur.Strata Florida Abbey, Ceredigion, Wales) =>
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            15 Aug 1275 bur.Strata Florida Abbey, Ceredigion, Wales) =>
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