The collegiate church of San Martino is a religious building located in the historic center of Cerreto Sannita.
First mentioned in 972, it constituted one of the six parishes of ancient Cerreto. On February 22, 1544, Bishop Alberico Giaquinto, with the consent of Count Diomede III Carafa and the universitas (municipal administration of the time), erected the church into a collegiate church, endowing it with a chapter of eleven canons plus the archpriest and unifying the other five parishes.
Razed to the ground by the earthquake of June 5, 1688, it was rebuilt in the center of the new urban fabric desired by Count Marzio Carafa and his brother Marino, thanks to funds provided by the universitas, the confraternity of the Most Holy Body of Christ and the feudal lords.
The collegiate church, characterized by the external stone staircase that divides into four branches, with its 2,000 m2 (22,000 sq ft) of surface area, 58.5 m (192 ft) in length, 32.4 m (106 ft) in width and 25 m (82 ft) in height, is the largest church in the diocese of Cerreto Sannita-Telese-Sant'Agata de' Goti. Inside it are preserved numerous 18th-century paintings, valuable wooden statues, some ancient Cerretese ceramic floors, a 19th-century organ in a Baroque case, and some altars made of inlaid polychrome marble.