Bruno di Segni was an Italian Roman Catholic prelate and professed member from the Order of Saint Benedict who served as Bishop of Segni and Abbot of Montecassino. He studied under the Benedictines in Bologna before being appointed a canon of the cathedral chapter of Siena. He was invited to Rome, where he became a bishop and counseled four consecutive popes. He served as Abbot of Montecassino but when he criticised Pope Paschal II regarding the Concordat of Ponte Mammolo in 1111 the pope relieved him of his duties as abbot and ordered Bruno to return to his diocese, where he died just over a decade later. Bruno's canonization was celebrated on 5 September 1181 under Pope Lucius III, who presided over the celebration in the late bishop's diocese.
