St. Thomas Church is associated with a number of well-known composers such as Richard Wagner and Felix Mendelssohn Bartholdy, but mostly with Johann Sebastian Bach who worked here as a Kapellmeister (music director) from 1723 until his death in 1750. Today, the church also holds his remains. Martin Luther preached here in 1539.
There has been a church at the current site of the Thomaskirche at least since the 12th century. Foundations of a Romanesque building have been discovered in the choir and crossing of the current church. Between 1212 and 1222 the earlier structure became the church of the new St. Thomas Monastery (Stift) of the Augustinian order.
The current building was consecrated by Thilo of Trotha, the Bishop of Merseburg, on 10 April 1496. The reformer Martin Luther preached here on Pentecost Sunday in 1539. The monastic buildings were demolished in 1541 following the monastery's dissolution. The current church tower was first built in 1537 and rebuilt in 1702. Chapels added in the 17th century and an ante-building along the northern front of the nave with two stairways were removed at the end of the 19th century.
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.