The first nucleus of the castle was built in the year 877 by a certain Francone with the agreement with the Abbey of Farfa. In the twelfth century, the castle passed to the Orsini family who ruled Mompeo for five centuries, building up the Castle with major extension work. The structure was developed on a circular plan with cylindrical towers. In 1646, the castle was transformed into a baronial building by the Naro family. Currently, of the old castle of the Orsini remain only two towers that provide an image of how the original fortress must have looked. Inside there is a courtyard and a loggia. Some rooms are frescoed by the Sabine painter Vincenzo Manenti and a painter from Arezzo, Salvi Castellucci.