In April 1082 he was travelling from Segni to Rome when Adolfo di Segni seized and imprisoned him. He was freed and returned to Rome but was imprisoned once more alongside the pope in the Sant'Angelo castle. Pope Victor III named him as the Vatican Librarian and he held the position until he left for Montecassino in 1099. Bruno had connections to Pope Urban II whom he accompanied to the Council of Clermont in late 1095 where the First Crusade was inaugurated. He travelled with the pope to Avignon from 11–13 September before setting off for Cluny on 25 October and to the council on 18 November. He accompanied the pope to Limoges from 23–31 December and then onwards to Charroux before going with him to Poitiers on 22 January 1096. Bruno accompanied Urban II to Moyenmoutier on 10 March before going to Tours from 14–20 March and then to Poitiers again from 30 March to 14 April. Their last two destinations were in Nîmes on 12 July and Saint-Gilles on 20 July. In 1099 he entered Montecassino convent without resigning his episcopal see or severing his relations with the outside world. He undertook a mission to the Kingdom of France for Pope Paschal II in 1106 remaining with the pope for several months after his return before returning to his cloister where he was elected as abbot for Montecassino in November 1107. Paschal II made no objection to this pluralism until Bruno condemned the pope's signing of the Concordat of Segni in 1111 was forced to resign his position as the abbot and return to Segni as its bishop. He and other Italian and French bishops rejected the "Privilgegium" that Emperor Heinrich V extorted from the pope in the latter's imprisonment and censured the pope in a letter for conceding to the king the right to investiture of abbots and bishops. His chastising the pope led to the frustrated Paschal II in turn chastising Bruno for shirking his duties and forced him to return to Segni. He served as a legate to France twice in 1104 and 1106 while he visited Civita Castellana with the pope on 8 September 1105 and in Parma on 2 November 1106. Bruno was also present in Segni to welcome the pope on 4 June 1109 who celebrated the canonization for Bruno's old friend Pietro di Anagni.