The imposing tufo mass of the Castle on the summit of the hill is one of the best-known sites of the city of Naples.
The castle as it now appears, with its six-pointed star structure, was the work between the years 1537 and 1547 on a design by Pedro Luis Escrvà of Valenzia, an expert in military architecture in the service of the Viceroy don Pedro de Toledo, whose name appears on the inscription over the entrance portal.