The castle was situated in the northern part of the location city next to Torun Gate. Its shape was quadrilateral leaning against city walls. From 14 century on, as the seat of the Starost (Mayor) this was a place of trials and city authority appointment. The great fire of the city in 1537 did significant damage to the castle. From 17 c. on the castle systematically fell into decline. It was totally destroyed in a fire of 1792, which consumed most of the city. In 1803 Prussian authorities sold the ruins of the city castle to a private person, who used it as construction material. A section of the castle uncovered during excavation works is now the Archaeological Reserve.