BOLIANO-CAMPOBASSO, DIOCESE OF. - B., a small town at the foot of a northern spur of the Matese, in the heart of ancient Samnium and modern Molise, in the province of Campobasso. It is recorded by Livy as a flourishing Samnite city; occupied by the Romans in 314 BC, it became a colony and municipality (Bovianum Undecimmanorum). Christianity in B. is attested by an undated Christian inscription (CIL, IX, 2584). With the Lombard invasion, it became part of the Duchy of Benevento as a gastaldate. In the 11th century it passed under Norman rule. Frequent earthquakes and a violent fire, set by Frederick II in 1221, brought about its ruin; as a result, from the 13th century onward, the population began to decline in favor of nearby Campobasso. The origin of the bishopric is uncertain. It is likely that the Laurentius who attended the Roman synods of 501 and 503 was bishop of B. The regular list of prelates begins only in the 12th century. The present diocese, a suffragan of Benevento, comprises municipalities in the provinces of Campobasso and Benevento. It has 100,000 inhabitants, all Catholic, 46 parishes served by 68 diocesan and 24 regular priests (1948). The Cathedral, built by a Rodolfo, Count of Boiano, and consecrated in 1215 by Bishop Poliziano, is dedicated to St. Bartholomew. It was restored and adorned in 1572 by Cardinal Carlo Carafa but was damaged in the recent war.
The episcopal see was transferred on 29 June 1927 to Campobasso, given the greater importance of that city, where the oldest churches are those of the Most Holy Trinity, now the cathedral, and of St. Leonard, both from the 13th century.