Sant'Angelo was constructed in the mid-16th century by the Spanish general and Governor Milan Ferrante Gonzaga, over an edifice already existing in 1418, in replacement of the eponymous one, which had been destroyed to build the new walls. The design was by Domenico Giunti. The small bell tower was added in 1607, while the façade was finished only in 1630, in late-Mannerist or early-Baroque style. The church is one of the few in the city which was not restored in 'neo-medieval' style during the 19th century.
It has a single nave with side chapels and barrel vault, a transept and a deep presbytery. Artworks include works by Gaudenzio Ferrari, Antonio Campi, Morazzone, Simone Peterzano, Ottavio Semino, Camillo Procaccini and Giulio Cesare Procaccini. The triumphal arch has a frescoes with a solemn Incoronation of Mary by Stefano Maria Legnani.
In the transept is the tomb of Blessed Beatrice Casati, the wife and widow of Francino Rusca, the Earl of Locarno. She raised four children -- three sons and one daughter, the latter of whom placed this monument to their mother -- and was a devout member of the Franciscan tertiaries. She died in 1490.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.