The monastery church of the Order of the Cross, built in 1443, has already fulfilled many different purposes. After the church was profaned in 1812, it served in the following years as a horse stable, tobacco warehouse of the customs authority and ammunition depot.
In 1968 they removed the installations of the 19th century, the windows were reconstructed in their original form and even the late Gothic frescoes could be preserved. After a new consecration in 1990, the building functions as a school church of the school in the Altstadt (Old town). But the crusaders responded again: In 2011 during the canal construction works in an underground vault not only remains of the first city wall were found, but also human bones. Evidence suggests that the vault belonged to the former Knights of the Crusader Monastery.