Jonh´s Castle was originally supposed to be much grander, but the project was reduced at the request of the prince. The building consists of four corner towers – each one with a different ground plan. The towers are connected from three sides by perimeter walls with first floor ramparts located on the outer sides. The fourth side of the courtyard is closed by a mansion.
On the first floor of the mansion there is the Knights Hall where the feasts and hunting banquets took place. Lounges are located in the towers. Only the South tower has a second floor with a balcony from which it is possible to cross a gallery to the second floor of the West tower. The third floor comprises of a lookout point on the South tower.
The unstable floodplain forest subsoil had to be reinforced by wooden beams. Only then could the work begin. Stones for the construction were brought from Pálava and the nearby Great Moravian settlement of Pohansko. In his effort to build as realistic imitation of a real castle as possible, the architect paid great attention to every detail, such as the right-handed turning staircase, privys and loopholes.