A castle of the Warmia bishops, sited in the fork junction of Rivers łyna and symsarna, was erected in the years 1350-1401. The brick building, square in plan, with an entrance gate from the south was never a part of the city fortification system. In the early 16th century the castle was reshaped and its interior was redesigned. In the 19th century it housed a hospital and a casern. Reconstructed after World War II, the Lidzbark Warmiński castle belongs to the most valuable monuments of the defensive architecture in Poland. Part of the interior decorations have been preserved. In the museum section of the castle we can admire collections of Gothic and Baroque arts as well as mementos connected with Nicolaus Copernicus (Milołaj Kopernik).