At the battle of Tinchebray (1106) he captured Robert Curthose, Henry I of England's brother and leader of the opposing forces as Duke of Normandy.
As bishop he was greedy and violent; he is portrayed in very unflattering terms in the 1115 chronicle Monodiae of Guibert of Nogent. He had Gerard of Quierzy murdered. His election as bishop was contested - at the time of the battle he was in minor orders only - but it was upheld by Pope Paschal II at the Council of Langres. He was murdered, beneath Laon Cathedral, by citizens of Laon who had set up a commune in the city. Guibert's account of this event alludes to Isengrin, making it of literary-historical value. .