Crusader. Commander under Godfrey of Bouillon during the First Crusade   [1] .

The first crusade, the only successful crusade, is an amazing story. It consisted of 4 divisions, of which 3 were more-or-less Norman. Godfrey of Bouillon, Duke of Lower Lorrain, commanded one of the Norman divisions, and Conon apparently served under him:

"A commitment to crusade, therefore, involved heavy expense and real financial sacrifices, and the burdens on families were even heavier if several members chose to go. This was common... the list is, in fact, almost endless... Conon of Montaigu, incidentally Godfrey of Bouillon's brother-in-law, and his sons Goscelo and Lambert... I have put down here only the closest relatives; ..." (Riley-Smith).

Conon played a role in a crucial negotiation the occurred when then Crusaders arrived at the gates of Constantinople. The Normans were traditional enemies of the Greeks and the Emperor Alexius (although they had originally served the Byzantines as mercenaries), and had spent the last 20-30 years absorbing the last lands of the Byzantines in Sicily and Southern Italy. Alexius, hard pressed by the Turks, had appealed to the Western Pope, but feared his "saviors" almost as much as his enemies. Godfrey sent 3 envoys to parley with Alexius: Baldwin of Le Bourg, Conon of Montaigu, and Geoffrey of Esch.

After the Crusade, Conon and his son Lambert founded a Priory:

"Peter the Hermit, who returned with relics of the Holy Sepulchre and St John the Baptist, joined Conon and Lambert of Montaigu in founding the Augustinian priory of Neufmoustier, at Huy near Liege, dedicated to these patrons. In the thirteenth century it was believed that this foundation stemmed from a vow made by the returning crusaders during a storm at sea." (Riley-Smith).

Anna Comnena , the daughter of the Byzantine emperor Alexius, is a famous historian of these events.

Sources:
The First Crusade, Riley-Smith.
A History of the Crusades, Runciman.

http://www.montaguemillennium.com/familyresearch/h_1096_conon.htm