[1][2] In 1191, the Béthune family, now including the younger brothers Baldwin and Conon, accompanied Count Philip I and their father on another pilgrimage to the Third Crusade.

When Robert VI died childless in 1193, William II inherited the Béthune family possessions.

Members of the Béthune family had divided loyalties in the conflict between King Philip II of France and Count Baldwin IX of Flanders about who was the rightful liege lord of Artois.

Conon and Cardinal Peter of Capua tried in vain, and according to de Villehardouin in tears, to persuade William to stay in Constantinople.

Married Mathilda of Dendermonde and had seven known children, the first five born by 1194:[4] William died in April 1214, a few months before the Battle of Bouvines.