Mathilde von Northeim 1053 - (b. 1053) Parents Otto of Nordheim Richenza of Swabia Children Frederick of Werl-Arnsberg Henry of Arnsberg Siblings Henry, Margrave of Frisia Siegfried III, Count of Boyneburg Kuno, Count of Beichlingen Ethelinde of Northeim Ida von Nordheim Oda von Werl Partners Conrad II of Werl-Arnsberg