The Gaeta Fortress, an Angevin-Aragonese castle in the historic center of Gaeta, currently houses the Mazzini barracks of the Nautical School of the Guardia di Finanza in the Aragonese part, and a peripheral headquarters of the University of Cassino in the Angevin part. Built in the 6th or 7th centuries, the castle was fortified by Frederick II of Swabia in 1223. With an area of approximately 14,100 m², it consists of two connected buildings from different periods, one "Angevin" and the other "Aragonese." Charles V fortified the fortress, making it one of the most imposing in Europe. Part of the building was used as a military prison and is now intended for university faculties of maritime disciplines. The Gaeta Tower, part of the Aragonese castle, houses the Royal Chapel, commissioned by Ferdinand II of Bourbon in 1849.
