Castel Sant’Elmo is a medieval castle and is the first castle by extension of the city). It originates from a Norman observation tower called Belforte. The Castle has always had a considerable strategic importance so much so that from its position you can control the whole city, the gulf, and the roads that lead from the surrounding hills to the city. The castle, as well as a permanent museum, the “Napoli Novecento”, is also home to various temporary exhibitions, fairs and events.
Built at the beginning of the fourteenth century the castle had a long history of sieges and was a military target when the French and Spanish fought the Kingdom of Naples. In 1707 it was besieged by the Austrians; in 1734 by the Bourbons. At the time of the French Revolution, the prison housed some pro-Jewish patriots: Mario Pagano, Giuliano Colonna, Gennaro Serra di Cassano, Ettore Carafa.
During the 1799 uprisings it was taken by the people and then occupied by the Republicans, who during the siege of the French forces, from here bombed behind the Neapolitan Lazzari who had risen to oppose the occupation of the city. The last resistance was swept away, on 21 January they planted the first tree of freedom and on 23 January they raised the flag of the Neapolitan Republic. After years of work to restore it was opened to the public on May 15, 1988; the castle belongs to the Civil Estate and is used as a museum.