What is the reason? The cathedral has an extensive defense system, and at the same time, documents from the thirteenth century define the cathedral as a castrum or just a castle as well. Looking at the building, you can count as many as eight towers and bastions (one more has not been preserved).
The oldest tower is the Copernicus Tower, bought by the local canon for 175 grzywna units. The most valuable building of the fortress is of course the cathedral, the jewel of Gothic architecture. It is one of the largest and most beautiful sacred buildings in north-eastern Europe.
