A participant in the First Crusade (1096-1099). The eldest son of Gozelo, count of Behogne (d. 1064), and Ermentrude of Harzé, Cono was more usually known as count of Mon- taigu (in mod. Belgium), after the castle on the river Ourthe in the northern Ardennes where most of his possessions lay. His family had long been prominent vassals of the ecclesiastical principality of Liège. Some of the older literature mistakenly claims that Cono was a brother-in-law of Godfrey of Bouillon, ruler of Jerusalem. There is no reliable evidence to support this claim, although it is likely that they were more distantly related.
In 1096 Cono sold property to the abbey of Saint-Hubert in the Ardennes to raise funds for the crusade, in which he and his sons Gozelo and Lambert took part as members of Godfrey’s contingent. Gozelo died of disease at Artah. After fighting at the battle of Ascalon (12 August 1099), Cono and Lambert returned home, reaching Liège by 10 March 1100. Cono died on 30 April 1106, and was succeeded by Lambert as count of Montaigu.