A painting on the altar and the statue in the chapel dedicated to Saint Michael, as well as a third work exhibited at the Diocesan Museum of Sacred Art, depict Saint Michael, patron saint of the city, in the act of defeating Satan. One of the most distinctive Christian buildings in Alghero is named after him and is located in the historic centre. The existence of the church is documented from 1364, after which, between 1503 and 1593, it was a pro tempore cathedral, awaiting the completion of Santa Maria. Its current appearance is a 17th century refurbishment: this work began in 1612 and it experienced a turning point when Bishop Bacallar gave the building to the Jesuits to manage, who also established their College there. The architect, Domenico Spontorno - responsible for the Cathedral of Ales and the reconstruction of that of Cagliari - handled the project, creating one of the most significant examples of Baroque style in Sardinia (1675).

The façade overlooks Piazza Ginnasio. It has a base in sandstone ashlars and a smooth wall, with three large windows and a wooden portal in it, above which there are bas-relief and high-relief sculptures that symbolise the Annunciation and the Holy Spirit. Its simplicity further enhances the majesty of the dome, symbol of the city. With an octagonal section and set on a high tholobate, it has multicoloured tile cladding and was designed by Antonio Simon Mossa and Filippo Figari (1950). The interior has a single nave, with a barrel vault divided into arches that rest on Corinthian columns. The presbytery is at the crossing point with the transept and above it is the dome. At the centre of the altar, there is a large painting of Archangel Michael. He is a constant presence in ‘his’ church: he returns in the impressive wooden statue in the chapel dedicated to him. There are three chapels on each side: on the left, the one dedicated to the Immaculate Virgin Mary, splendidly decorated with stucco on the sides, ‘describes’ scenes from the life of the Virgin Mary, who is portrayed, in the main painting, with her feet on the moon, surrounded by angels and with the Holy Trinity above her. The chapels of the transept and that of the Madonna della Freccia (Madonna of the Arrow) have monumental baroque altars: you will be struck by the perfection and meticulous care taken in the decoration. Every year, Alghero dedicates the celebration of Sant Miquel (in Catalan language) to its patron saint: twelve days of religious celebrations and cultural shows at the end of September.