The sanctuary of S. Silviano, located halfway up the hill of Monte Leano, is one of the most important and oldest religious buildings of the Terracina territory, characterized by a continuity of life documented from the archaic age to the Middle Ages, when the church of the monastery took the name of S. Silviano. During the 10th-11th centuries the prosperity of the monastery shows the large spread of the cult of Silviano in the territory of Gaeta and Terracina. It was celebrated in the round chapel, structurally connected to the apse of the church. In the late Middle Ages, the decoration of the Chapel was made in two different chronological phases. The fresco paintings of the saints Rufina, Cesareo and Eleuterio are datable to the seventh-eighth decade of the 13th century, similar to the style of Roberto di Oderisio. The portrait of the Silviano within the recess of the chapel appears stylistically comparable to the style of Giovanni da Gaeta and datable to the fifties-sixties of the 15th century. The mural painting belongs to the second decorative phase (fifth or sixth decade of the 15th century).