During the course of the 15th century, windows encased in gothic architecture were installed on the South side (with 6 statues of electoral princes) and double-windows on the East side. The ornamental astronomical clock was installed around 1520. The lavish exterior murals were extended to the older part of the building and didactically illustrate virtues, commandments and vices. The paintings visible today originate from the year 1900 when the previous paintings, which had been largely destroyed by the weather, were restored or renewed in the sprit of the surviving remains.