Mahaut de Saint Omer (1110-1169) (1109–1168) Parents Guillaume II, Châtelain de Saint Omer Millesende de Picquigny Children Adélide de Guines Baldwin II, Count of Guînes Béatrix de Guines Marguerite de Guines Siblings Walter of Saint Omer Guillaume III, Châtelain de Saint Omer Partners Arnold I, Count of Guînes