In 474 BC, Hiero I of Syracuse founded the Castrum Gironis atop a 113-meter-high volcanic rock formation off the coast of Ischia. Today's Aragonese Castle, built on a trachytic islet formed over 300,000 years ago, acquired its modern quadrangle shape in 1441 when Alfonso V of Aragon fortified the site, drawing inspiration from Naples' Maschio Angioino. A 220-meter masonry causeway connects the citadel to the historic Borgo di Celsa.
What to see
Visitors enter via a 400-meter tunnel carved directly into the rock by order of Alfonso V, built with high openings that served both as skylights and machicolations for defense. Inside the tunnel stands the Votive Chapel, excavated in 1441. Higher up, the Church of the Immacolata—begun in 1737 under Abbess Giovanna Battista Lanfreschi—dominates the citadel with its large dome. The 56,000-square-meter grounds contain the ruins of the Cathedral of Assunta, the former Poor Clares convent, terraced vineyards, and steep cliffs. During its 16th-century peak, when nearly 1,900 families resided on the rock, poet Vittoria Colonna lived here, turning the castle into a literary hub for figures like Michelangelo Buonarroti, Ludovico Ariosto, and Jacopo Sannazaro.
Visiting
The upper area can be reached on foot along an outdoor mule track or via an elevator constructed inside the rock shaft during the 1970s, which rises 60 meters. Sold at auction to private owners in 1912, the property is regularly restored and open to visitors year-round. From late June to early July, the castle grounds serve as the venue for the Ischia Film Festival.
Our editors' tip
Look up while walking through the entry tunnel to observe the vertical machicolations overhead, engineered in the 15th century to drop boiling liquids and stones onto invaders.