The first information about Brodnica as a town comes from 1317. At that time, the construction of brick defense walls began, which ended in 1370 with the extension of two municipal gates: Masuria and Chełmno Gate. The final shape obtained the form of a double line of walls with fifteen towers and a moat. Around the middle of the 19th century, after losing the defensive meaning, the walls began to be gradually demolished, or incorporated into the structure of newly erected buildings.
The brick walls of Brodnica consisted of a defensive wall reinforced with fifteen towers and a moat. There were three gates leading to the town: Masuria, Grudziądz and Chełmno. The Chełmno Gate, also called Stone Gate, is located in the northern part of the town. It is made of brick, on a plan similar to a square with a pointed passage, decorated on two sides with blendes. On the western side of the passageway, a fragment of the gates wall has been preserved. The Masuria tower is located on the bank of the Drwęca river, in the southern part of the town. It was part of the not preserved Masuria Gate. The ground floor of the tower has the form of a rectangle, above it goes into an octagon. It is covered with an eight-field roof.
Currently, the best-preserved elements of fortifications are the Chełmno Gate, the Masuria Tower and the section of the wall at Kiliński, Przykop and Zamkowa streets. In the north-east corner of the Old School Square there is a fragment of a polygonal tower that is open from the town side. At present in the Chełmno Gate there is a branch of the Museum of Brodnica.