Built in the second part of the XII century for the Guglielmo I "Il Malo"'s will, the castle, that rises in the proximity of the ancient Porta Capuana ( from which it took the name) was the residence of the emperor Federico II of Svevia and, after the construction of the more comfortable palace of Castel Nuovo (1729) was many kings, princes and dignitaries of the angevin and aragonese dinasty's residence (Ladislao, Giovanna II, Alfonso duke of Calabria).
During the modern age the castle was the background of convulsive political events of our city that brought to the succession of different foreign dominations of the southern reign. In 1540 for the viceroy don Pedro de Toledo's will the castle became a Law Courts and it has preserved this function till today.
From the majestic portal, overcome by the escutcheon with the insignia of Carlo V, one can access in the rectangular yard and from a great staircase one can go up in the huge Salone della Corte d'Appello with the illusionistic architectonical perspective and the architectonical figures of the 12 province of the Reign of Naples, realized by Antonio Cacciapuoto and helps (1770 c.). Noteworthy are the wonderful decorations and the frescos of the sixteen century Chapel of Sommaria, portraying scenes of the New Testament, work of Pietro Ruviale, too.