Nielsen Hayden genealogy
Descendants of William de Monmouth
1065 - Bef 1138 (~ 77 years)Father: Baderon de Monmouth (of La Boussac, Brittany, France - ??)
William de Monmouth (Between 1060 and 1065 of Monmouth, Monmouthshire, Wales - Bef 1138)
   └─ Baderon de Monmouth (Abt 1100 Monmouth, Monmouthshire, Wales - Between 1170 and 1176)
    Rohese fitz Gilbert ( - Bef 1166)
       └─ Rohese de Monmouth (Between 1135 and 1140 - Abt 1180)
        Hugh de Lacy (of Meath, Ireland - 25 Jul 1185)(m. Bef 1155)
           │ + William Fitz Alan (Abt 1154 of Oswestry, Shropshire, England - 1210)(m. Abt 1175)
           │ + Margaret de Briouze (Abt 1181 - Aft 25 Jun 1245)(m. Bef 19 Nov 1200)
           └─ Hugh de Lacy (Abt 1176 -
            Bef 26 Dec 1242 bur.Convent of the Franciscan Friars, Carrickfergus, Antrim, Ireland)
            Bef 26 Dec 1242 bur.Convent of the Franciscan Friars, Carrickfergus, Antrim, Ireland)
            + Emeline de Ridelisford (of Bray, Berkshire, England - Between 18 May 1275 and 19 Jul 1276)
            + Lesceline de Verdun (m. Abt 1195)