 The most famous monument is the Palazzo Ducale, that was built by Alonzo III who belonged to Sanchez de Luna d'Aragona's family.Before it was built, there was an old church, that was destroyed and was substituted by the palace.In 1903 the palace was bought by Giuseppe Macrì who gave it to the people who lived in Sant'Arpino and today it is the town's head office of the municipality.