Since the bishops themselves held the fief of Conflans-Sainte-Honorine from the French crown, the lords of Montmorency began to call themselves the "First Barons of France".
[1][2] In the mid 1080s, war broke out between Bouchard and his brother-in-law Mathieu I, Count of Beaumont-sur-Oise and heir to Yves II, over the Beaumont inheritance.
Having gathered a royal army, joined by troops from Count Simon II de Montfort, Count Robert II of Flanders and Princess Adela of England, Louis marched against Bouchard in 1101, ravaged his lands, and besieged him in the castle of Montmorency, forcing him to surrender.
The calendar of the episcopal Church of Amiens commemorates him on 12 January, and on the basis of an entry in the memorial book of the Abbey of Notre-Dame-du-Val, it has been suggested he died in Jerusalem in 1132.
[1][4] Bouchard's first marriage (before 1086) was to Agnes de Beaumont, (died before 1105) lady of Conflans-Sainte-Honorine daughter of Yves II, Count of Beaumont-sur-Oise.