Count Otto of Loon (d. abt 1087), was ancestor of the Count of Duras, and brother of Emmo van Loon, ancestor of the Counts Loon. In contemporary and later medieval records he is mainly known for his role as advocate of Sint-Truiden Abbey, which is today in Belgian Limburg. Otto married Oda, daughter of Giselbert I, Count of Duras. Otto and Oda had children: * Giselbert II, Count of Duras * Gerard of Bertrée, Prior of Bertrée * Hériman de Duras. (Named by Wolters in 19th century. Not named by more recent scholars.)