One of the many castles built by the Germanic Teutonic Knights was built in Łagów in the 14th century. At the beginning of the 15th century the castle and lands of Łagów were in hands of a fierce Polish knight named Marek, who became bitter and lonely after the death of his wife. The local people all disliked Marek, but he had a beautiful and likeable sister named Dorota.
One fine spring day in a battle just outside of the town, the knight caught and imprisoned a Prussian prince by the name of Boris. Prince Boris was put into a dungeon, and able only to sing in order to keep his sanity in the deep, dark, and damp dungeon. After several months his voice became very musical and townspeople flocked to the castle to listen to his wonderful singing.
Indeed he sang so beautifully that the knight's sister became so captivated by his voice that she fell in love, without ever having once seen the Prussian Prince. One night she bribed the guards and Prince Boris and Dorota met for the first time. After many such meetings they were deeply in love with each other and wanted to be married.
Unfortunately for them Marek would hear nothing of the match and the princess was informed that she would instead be married to an elderly Polish knight from the neighbouring town. Dorota could do nothing but obey her brother. During the enforced wedding Prince Boris, her Prussian lover, was called up from the dungeon and asked to sing for the many gathered guests. He refused and the angry knight immediately gave the order to behead him and his body to be thrown into the nearby lake. The beautiful Dorota who witnessed the whole terrible incident, died soon afterwards from a broken heart. Her distraught soul is said to wander the lakeside, town and castle in Łagów to this very day. Locals say that on fine summer evenings the ghostly voice of Boris can be heard from the castle's dungeon and from the waters of the lake.