Nielsen Hayden genealogy
Descendants of Constance ferch Owain
Father: Owain Cyfeiliog ap Gruffudd ap Maredudd ap Bleddyn ap Cynfyn (Abt 1130 - 1197 Monastery of Strata Marcella, Welshpool, Montgomeryshire, Wales)
Mother: Gwenllian ferch Owain
Constance ferch Owain
   └─ Idonea de Malpas ( - Bef 1295 Malpas, Cheshire, England)
    Urian de St. Pierre (1220 - Between 1290 and 1300 Cheshire, England)
       ├─ Katherine de St. Pierre ( - Aft 1296)
       │ Randle le Roter ( - Bef 1296)
       │    └─ Peter Thornton (Abt 1292 - Between 1351 and 1358) =>
       │     + Lucy de Hellesby
       └─ John de St. Pierre (1246 - 1290)
        Katherine Dutton ( - Aft 1292)
           │ + Philip de Egerton
            + Isolda de Grey