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 Amphitheatre of the Three Gauls was part of the federal sanctuary of the three Gauls dedicated to the cult of Rome and Augustus celebrated by the 60 Gallic tribes when they gathered at Lugdunum (Lyon). The amphitheatre was built at the foot of the La Croix-Rousse hill at what was then the confluence of the Rhône and Saône.
Excavations have revealed a basement of three elliptical walls linked by cross-walls and a channel surrounding the oval central arena. The arena was slightly sloped, with the building"s south part supported by a now-vanished vault. The arena"s dimensions are 67,6m by 42m. This phase of the amphitheatre housed games which accompanied the imperial cult, with its low capacity (1,800 seats) being enough for delegations from the 60 Gallic tribes.
The amphitheatre was expanded at the start of the 2nd century. Two galleries were added around the old amphitheatre, raising its width from 25 metres to 105 metres and its capacity to about 20,000 seats. In so doing it made it a building open to the whole population of Lugdunum and its environs.