Jan van Oostervant 13th century noble, earl of Oostervant, Flanders (d. 1302) Parents John I of Hainaut Philippa of Luxembourg Children Siblings Alice of Hainault Willem Cuser John of Beaumont Aleida de Hainaut Isabelle of Avesnes Simon Heer van Bruelis Marguerite d'Avesnes William I, Count of Hainaut Mary of Avesnes