Nielsen Hayden genealogy
Descendants of Siegfried I of Blankenburg
Father: Poppo I of Regenstein-Blankenburg (Abt 1095 - Abt 1164)
Mother: Richenza von Boyneburg
Siegfried I of Blankenburg
   └─ Heinrich I of Blankenburg and Regenstein
    (Unknown) von Polleben
       └─ Ulrich I von Regenstein ( - Between 24 Jun 1265 and 5 Jun 1267)
        Mathilde (m. Bef 1236)
            + Heinrich II of Honstein ( - 24 Jan 1284)(m. Bef 1253)