Otto married Philippa De Dammartin, [COUNTESS OF GUE in 1252/1253 in , Boves, Somme, France. Philippa (daughter of Simon Ii Count Dammartin, [COUNT OF AUMALE and Marie (Jeanne) Countess Ponthieu & Montr, UIL) was born about 1214 in Of, AUMALE, Seine-Maritime, France; died in 1271 in Of, Zutphen, Gelderland, Netherlands. [Group Sheet] [Family Chart]