Alghero was designated as a diocesan seat in 1503 but construction work on the cathedral did not begin until 1567. It was inaugurated in 1593 but was not finished. After several restorations it was consecrated in 1730.
The church was originally in Catalan-Gothic style, as can be seen in the five chapels and ambulatory of the presbytery, which also includes the octagonal base of the bell tower. The nave and the two aisles are however in Late Renaissance style. The main altar was designed by the Genovese artist Giuseppe Massetti (1727): the sculpture shows Mary the Immaculate flanked by angels. He also designed the ambulatory and the pulpit. In 1862 a Neo-Classical narthex was added to the façade, which dramatically changed its appearance.
The first chapel on the right side is dedicated to the Blessed Sacrament. Its imposing, marble altar was inaugurated in 1824. It is located inside a circular temple, reminding the Temple of Vesta in Rome.
The cathedral is the burial site of the Italian-born Duke of Montferrat (1762-1799) and his brother Count of Asti (1766-1802) who died on the island having caught malaria. The marble mausoleum was sculpted by Felice Festa in the early 19th century.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.