A fortress built by Guglielmo I d'Altavilla in the 12th century and restored in the 13th century by Carlo d'Angió, this castle was transformed into a royal residence by the Aragona dynasty in 1484. In 1540, Don Pedro di Toledo, the viceroy of Naples, decided to change the residence to the seat of tribunals, a function it has maintained to this day. Less dramatic than the other fortresses in Naples, Castel Capuano takes its name from the nearby gate, Porta Capuana, that once stood at the head of the main road leading to Capua. Inside the courtyard, the medieval structure is visible. You can visit some of the decorated halls and the Cappella Sommaria, with its 16th-century frescoes.