Nielsen Hayden genealogy
Descendants of (Unknown mistress of Friedrich II)
(Unknown mistress of Friedrich II)
Friedrich II, Holy Roman Emperor (26 Dec 1194 - 13 Dec 1250)
   └─ Margherita de Svevia ( - Between 1297 and 1298)
    Tommaso d'Aquino (Abt 1220 - 14 Mar 1273 bur.St. Maria delle Monache, Capua, Campania, Italy)(m. 1247)
       └─ Isabella d'Aquino
        Guglielmo II Etendard ( - Aft 1281)
            + Roberto d'Alneto