According to tradition, the church was dedicated to St. Mark, patron of Venice, after the help given by that city in the war against Frederick Barbarossa in the 12th century. However, the first mention of the church dates from 1254 when the Augustinians built a Gothic style edifice with a nave and two aisles re-using pre-existing constructions.
The structure was heavily modified in the Baroque style during the 17th century, when it became the largest church in the city after the Duomo di Milano.
In early 1770, the young Mozart resided in the monastery of San Marco for three months and, on May 22, 1874, the first anniversary of the death of the Milanese poet and novelist Alessandro Manzoni was commemorated in the church by the first performance of Verdi's Requiem, written in his honour.
The façade dates from an 1871 restoration by Carlo Maciachini, who kept the marble portal with tympanum, a gallery of small arches, the rose window and three statues of saints attributed to Giovanni di Balduccio or the Master of Viboldone. In the lunette is a mosaic representing the Madonna between Saints, a copy of the original by Angelo Inganni.
The campanile dates from the 14th century. It was restored and completed in 1885. The interior, in the Baroque style, has a nave and two aisles.
In the first chapel on the right are frescoes by Gian Paolo Lomazzo. In the right transept is a fresco by the Fiammenghini with Alexander IV Instituting the Order of the Augustinians, under which a 14th-century Crucifixion was discovered in 1956. The author of the latter has been identified by Anovelo da Imbonate. The right arms of the transept houses also several sarcophagi from the mid-14th century, including the tomb of Lanfranco Settalo, counsellor of Archbishop Giovanni Visconti, by Giovanni di Balduccio.
Near the rear exit is a 16th-century tombstone portraying the Angel of the Resurrection, another fresco by the Fiammenghini (under which is a 14th-century fresco). On the side walls of the presbytery are the Dispute of St. Ambrose and St. Augustine by Camillo Procaccini and the Baptism of St. Augustine by Giovanni Battista Crespi.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.