This historically significant church of the Lesser Town is currently located on the street, Josefská. Unfortunately, it is in the rather cramped area of the Lesser Town. It was established after the year 1285, at the same time as the arrival of the Order of Augustinian, during the reign of Václav II, who invited the Augustinians to Bohemia. This three-nave Gothic church was completed and consecrated in 1379, a year after the death of Emperor Charles IV. The Augustinians were an eyesore for the Hussites, who burned down their monastery and church in 1420. The Church was renewed at the end of the 15th century but during the fire of the Lesser Town in 1541, it was burned down again. The Renaissance reconstruction of the church took place in the 16th century and during the Rudofine Time, the church became rather important and popular. The Rudolph architect, Ulrico Aostali, or the Dutch sculptor, de Vries, are buried here. The ceiling frescoes are by Václav Reiner. The main altar is decorated with the paintings, Martyrdom of St. Thomas and a portrait of St. Augustine. These paintings were ordered by the prior of the monastery from the painter, Peter Paul Rubens. The originals of these paintings are in the National Gallery in the Sternberg Palace. Visitors can also find here statues of Maximilian Brokoff and Jerome Kohl or paintings by Karel Škréta. The current appearance of the church and the overall redevelopment came from the Baroque reconstruction and it was designed by Kilian Ignaz Dientzenhofer.
Local Augustinians were also famous for their excellent beer, which supplied the entire left bank of the Vltava. In the 16th century, they were the exclusive suppliers of beer for the Castle. Therefore, it is kindly recommended to visit the renowned, St. Tomas Beer house, and to try the local beer.