Saint William's Church is a gothic church is known for its sumptuous interior combining the Gothic and Baroque styles. Since the end of the 19th century, the excellent acoustics of the church has allowed it to serve as a venue for concerts of classical music, in particular for the Passions of Johann Sebastian Bach.
Returning unharmed from the Crusades, the knight Henri de Müllenheim undertook the construction of a monastery for the Hermits of Saint William, an order of mendicant monks, in this marshy neighbourhood situated extra muros, that is, beyond the city walls. The elongated building, consecrated in 1301 and realised in 1307, is the only remnant of this group. Entirely brick and unvaulted, the church corresponds well to the ideal of the order, namely by its single nave and the simplicity of its exterior form. Sheltered by a pitched roof, its nave is topped and prolonged by a deep polygonal choir illuminated by high windows, which betrays its original function as the monks' meeting room. In 1331, by reason of its proximity to the port and wharfs, the church was chosen as parish by the newly established corporation of shipbuilders.
References:The Chapel of St. Martin is the only completely preserved Romanesque building in Vyšehrad and one of the oldest in Prague. In was built around 1100 in the eastern part of the fortified outer ward. Between 1100 and 1300, the Rotrunda was surrounded by a cemetery. The building survived the Hussite Wars and was used as the municipal prison of the Town of the Vyšehrad Hill.
During the Thirty Years’ War, it was used as gunpowder storage, from 1700 to 1750, it was renovated and reconsecrated. In 1784, the chapel was closed passed to the military management which kept using it as a warehouseand a cannon-amunition manufacturing facility. In 1841, it was meant to be demolished to give way to the construction of a new road through Vyšehrad. Eventually, only the original western entrance was walled up and replaced with a new one in the sountren side. The dilapidating Rotunda subsequently served as a shelter for the poor.