The Cathedral of Trivento is certainly the most significant monument of the Molise town, in which are preserved most artistic documents.
Result of numerous stratifications, the cathedral preserves from the most ancient phase, in addition to an inscription of 1076 with the dedication to Saints Nazario and Casto, a series of hanging arches that at times crown it externally and the crypt of the century XII which, in turn, is the result of other stratifications.
From the right side aisle, you enter the crypt of San Casto which, according to tradition, was built on a temple dedicated to Diana.
In the crypt, there is a Roman inscription dedicated to this divinity.
It's divided into seven small longitudinal and three transverse naves, with round arches and cross vaults supported by columns and pillars.
On the altar, there is a 13th century stone lunette with a bas-relief depicting the Trinity flanked by two angels and two dolphins.
Among the three wooden sculptures, there is a Madonna enthroned from the 13th century.