Bruno of Segni was an influential 11th-century Italian Benedictine prelate who served as both the Abbot of Montecassino and the Bishop of Segni. Educated in Bologna, he became a prominent theologian known for defending orthodoxy during the Sixth Roman Synod. Throughout his career, he acted as a trusted advisor to four successive popes, accompanying them on significant travels including the Council of Clermont. Although he held high ecclesiastical offices, his tenure as abbot ended after he voiced criticism regarding the Concordat of Ponte Mammolo to Pope Paschal II.