The Castle (also known as Casteddu de Susu in Sardinian and Castello Superiore in Italian) is the main historic district of the city of Cagliari. Located on a dominant position on a limestone hill, about one hundred meters above sea level. This district was founded in the 13th century by the Pisans, who turned it into a fortress with walls, towers, and bastions. The seats of civil, military, and religious power were transferred here from the old judicial capital of Santa Igia, which the Pisans had previously destroyed, marking the end of the Kingdom of Cagliari. Since then, the Castello district has been the center of power and noble residences, under every domination, from the Pisans (13th-14th century) to the Aragonese-Spaniards (14th-18th century) and the Piedmontese (18th-19th century), until the post-war period. The Castello district is so closely linked to the city itself, which in Sardinian is called Casteddu. Even today, access to the district is through the ancient medieval gates, which open in the walls that surround most of the Castello, isolating it from the rest of the city. The walls surrounding the Castello district include the Tower of the Elephant and the Tower of San Pancrazio. Currently, the Castello houses important institutions such as the Prefecture and the Council Chamber of the Metropolitan City of Cagliari, which are located in the Royal Palace, situated in Piazza Palazzo. The Parish of the Castello is dedicated to Santa Cecilia and has its headquarters in the Cathedral Church, which is the main church of the Archdiocese of Cagliari. The University of Cagliari also has its main headquarters in the Castello district, in an eighteenth-century palace that houses the Rectorate offices. The Castello district offers numerous reasons for a visit, both for the numerous historical and artistic testimonies it houses, and for the picturesque places that can be discovered by walking through the narrow streets, stairs, and small squares that open up like terraces with enchanting views. The dark corners of the palaces, once sumptuous noble residences and now often fascinating testimonies of a bygone era, add a touch of decadent charm.