The first written records of the town date back to the 13th century. The ruins of a Teutonic castle, a Gothic church dedicated to St. Catherine of Alexandria, and the Chełm Gate are all remnants of the town's history dating back to the times of Copernicus. The city walls and fragments of the Gothic town hall also date back to the Middle Ages. The Copernican heritage is also referenced by the astro-base located at the local high school. There is also an intriguing story connected with Brodnica and Copernicus' work. In 1823, a book was published here in which Friedrich August Zermann, later the distinguished mayor of Brodnica, attempted to refute Copernicus' theories.