Located on the west side of the Castle, the Cathedral of Assumption is used for the screening of the works of the official selection, and for the meetings with the authors.
The Cathedral was built by people of Ischia after the Arso volcanic eruption (1301), in order to replace the destroyed one. The building was realized above a pre-existing chapel. In the years of the Risorgimento and in particular on 27 December 1509, the wedding day of Vittoria Colonna and Ferrante D’Avalos(marquis of Pescara), the Cathedral enjoyed its greatest rise in popularity. Originally the Cathedral was in Romanesque style; it was redefined in the 15th Century according to the style of that era, and again in the 1700s with Baroque style. The Cathedral collapsed in 1809 because of the cannon shots thrown by British. The Cathedral has three naves. The two side naves have cross vaults. A restoration programme is being carried out for the strengthening of the supporting structures and for the preservation of plasters of the 18th century.
On the detailed map of Aragonese Castle, the Cathedral of Assumption is marked by the number 19.