A later charter dated 1182 witnessed by Henri of Esch (a relative of Goffrey of Esch, compatriot of Conon I, Count of Montaigu), identifies Conon as Count of Montaigu and Duras.
In 1185, Conon and his brother Pierre donated all his properties to Sainte-Marie and Saint-Lambert in Liege.
These properties were not kept by the Bishop of Liege, who sold them to Gérard of Looz and Wéry of Walcourt.
Since Conon failed to answer the Duke's summons, the latter seized his properties, keeping some and selling others to Count Gérard of Looz in 1189.
Conon attempted to sell his advocacy to the Duke of Brabant who then occupied Duras and harass St Truiden, leading to an armed conflict involving also the Count of Hainaut.