This church is considered to be one of the most valuable early Baroque monuments in Prague. It was formerly the primary church of the Jesuits in the Czech Republic. The church is currently used by the Roman Catholic Academic Parish, and is a venue for organ concerts. The organ, whose origins date back to the 17th century, was played in the 1880s by Jakub Jan Ryba, celebrated composer of the Christmas Mass “Hey, Master!”.
One of three churches located at the Clementinum is the Early Baroque Church of the Holy Saviour. The front of the church faces Charles Bridge and stands at the site of a former Dominican monastery and St Clement Church. Hussites burned down the monastery during the Hussite Wars. The arrival of the Jesuits in Prague in 1556 marked the beginning of busy construction. The original buildings were torn down and work begun to build an extensive Jesuit complex on the sizable piece of land, This complex was called the Clementinum.
The church was built in several stages from 1578 – 1714. Major artists contributed to the remodelling work. Initially these were mainly the architects Carlo Lurago and Francesco Caratti. The line of columns and stuccowork in front of the entrance was created by Giovanni Bartolomeo Cometa. The statues in the portico are the work of Johann-Georg Bendl: Church Fathers, saints, evangelists, Christ and the Virgin Mary.
Based on a design by architect Franciscus Maxmilian Kaňka, both towers were raised and a cupola was added to the roof in 1714.
The interior and furnishings were reconstructed in 1971 – 1987, and in 1994 – 2008 the façade, portico and statues were repaired.
The Early Baroque interior is richly decorated with stucco, again the work of Giovanni Bartolomeo Cometa. The statues inside the church were made by Johann-Georg Bendl. The confessional decorated with statues of the twelve apostles is particularly noteworthy. A painting by Johann-Georg Häring is at the main altar. The underground crypt contains a large tomb for members of the Jesuit Order, including the guardian of the Czech language, Bohuslav Balbín. The church belongs to the Roman Catholic Church.
Source: https://www.prague.eu/en/object/places/1715/church-of-the-holy-saviour-kostel-nejsvetejsiho-salvatora