Castle of Peñíscola (Papa Luna) Monument · Peníscola, El Baix Maestrat, Castellón A Templar fortress built between 1294 and 1307 on the remains of an earlier Arab fortification, with the sober, solid lines typical of the order. In 1411 Pedro Martínez de Luna, Pope Benedict XIII, known as the Papa Luna, settled in it and turned it into a papal palace and library, a residence he used until 1423; his successor, Clement VIII, also lived there. It preserves the papal basilica, with a semicircular apse and barrel vault, the throne room, the conclave chamber and the pontifical study overlooking the sea. During the Germanías and under Philip II the engineer Juan Bautista Antonelli reinforced its defences against Barbary piracy. Declared a Bien de Interés Cultural (Spain's highest level of heritage protection) on 3 June 1931, it is today owned by the Diputación de Castellón. Photo: Gabriel Villena from Albacete, España (CC BY 2.0) What to see and do in Peníscola