The monastery, originally named after St. John, was founded by the Benedictines between the 10th and 11th centuries on the site where an early medieval structure that welcomed pilgrims passing through on their way to Monte Sant’Angelo already existed; in 1311 it passed to the Cistercians and in 1568 to the Friars Minor. Following the suppression of the monastic orders in the 19th century, it passed to the state and then to the Municipality of San Marco in Lamis, but during the 1900s the complex once again returned to the Franciscans, who became its owners following a donation from the municipality. The church has a single nave, with a monumental high altar in polychrome marble, a valuable work of Neapolitan masters, which in the aedicule above it holds a unique 16th-century statue of St. Matthew Blessing (the book the saint is holding bears the date 1596); according to some, the work is nothing more than the skillful transformation by an anonymous friar of an earlier statue of Christ, reshaped with the likeness of the evangelist saint as a result of the veneration paid by the faithful to a relic of St. Matthew (a molar tooth), which came almost at the same time as the passage of the convent to the Franciscans. Baroque side altars are dedicated to St. Joseph (1689), the Immaculate Conception (1690), St. Anthony of Padua (1692), and St. John the Baptist (1719). The exterior gives a good idea of the grandeur of a complex that has all the appearance of a fortress and is a reminder of the many contributions due to the uninterrupted presence of various religious communities over the centuries; of note are the cloister, with its large and elegant stone well, the rich library that holds more than 60,000 volumes and a relevant collection of archaeological finds.
