The Romanesque basilica is the oldest existing church in the area of the Prague Castle, was founded about 920, the present Romanesque church is building from the 11-12 century. At the church there was the first Benedictine convent in Bohemia, founded in 973. The church was reconstructed in the baroque style in the 17 century. In 1976 it was modernly adapted for the collections of old arts of the National gallery.