Among the works inside the church, there is the altarpiece portraying The Sermon of Saint John the Baptist by Girolamo Buratto or Buratti. The church is the home of the “Giovanni da San Gugliemo” Museum of Sacred Art. The most important works here are silver pieces by Domenico and Antonio Piani from Macerata and two busts of Saint Cassian. The museum also preserves numerous liturgical objects: reliquaries, chalices, crosses, pieces from goldsmith shops in Rome and in the Marche.