The original castle, called then Rheden, was built in 1234 on the initiative of Hermann von Balk on the isthmus between two lakes, which ran route from Grudziądz to Golub and Toruń. At that time, it was still a wood and earth stronghold, but despite this it managed to defend itself during the first Prussian uprising in 1242-1249. In 1251, Radzyń became a commandry, which certainly led to the decision to replace the timber structure with a brick one. These works may have lasted from the end of the 13th or the beginning of the 14th century, although the latest researches placed it to the period around 1320-1350. The perimeter of the outer walls of upper ward and fortifications of the outer bailey were erected a little later, in the second half of the fourteenth century.
In 1410, after the battle of Grunwald, the castle was captured by Polish troops returning from near Malbork. King Władysław Jagiełło leased it to Jasiek Sokoł from Lamberk, the commander of Czech troops fighting on the Polish side, and the Polish-Czech crew remained in the castle. Among it was, among others Jan Žižka, later a great commander of the Hussite Wars and a Czech national hero. Henry von Plauen tried to take the castle back, but the crew not only defended themselves, but also made a successful night raid to the town, causing great losses for the Teutonic Knights.
After the peace of Toruń in 1411, however, the castle returned to the Order. The effects of the war were long felt, and the garrison shortages so significant that only six knight brothers and the commander Henryk Hold lived in the castle. The order rule required that the convent‘s castle be staffed with at least 12 order knights. During the next war, which broke out in 1454, just two weeks after its outbreak, union troops stormed and captured the stronghold. Two years later, the mercenaries of the Teutonic Order tried to take the castle back, but as a result of the slipping of a part of the wall, a dozen or so besieging troops were killed and the attack collapsed.
After the thirteenth-year war castle was within borders of the Royal Prussia, and since 1454 it has been the seat of Polish starosts. During the Polish-Swedish war in 1628 it was seriously damaged during the siege of the Swedes and then abandoned. After the takeover by the Prussian authorities in 1780, successive demolition began. It was only in 1838 that the ruins were secured. Conservation work with partial reconstruction was carried out in 1961-1968.
The upper castle, considered as a model example of the convent’s seat in the order state, was built on an almost square plan with dimensions of 51×52 meters. This quadrangle was surrounded by an external wall and a deep moat provided with retaining walls. In the corners stood four slender towers on square plans, and from the north-east rose a large, octagonal main tower. The oldest and most important south range had shorter elevations decorated with gothic gables. The outer façades of the main castle were covered with a decoration made of zendrówka bricks in the form of regular diamonds.
The cellars were under all ranges. In the ground floor there were economic rooms, the floor was occupied by representative rooms and the convent’s chambers. Both basements and ground floor rooms were two-aisle. Its pillars were made of granite or bricks and carried groin vaults, rarely rib ones. On the upper floor in the eastern part of the southern range there was a chapel with three spans and a stellar vault. It was unusually two-sided ended. A sacristy was placed next to it in the corner tower. On the opposite side of the southern range there was a refectory, warmed by an accumulation furnace. The eastern range housed a stellar vaulted chamber, which until recently was considered as a chapter house. In the light of recent research, however, its existence has been questioned, and the room can be considered as the second refectory or just a representative room. From the north, a dormitory adjoined it. In the west range there was a commander’s chamber and a passage to the densker, in the form of a tower on stone supports. From the north there was an infirmary and a kitchen in the ground floor. The inner courtyard was surrounded by two-storied, brick and vaulted cloisters. Vertical communication was provided by two round staircases in the wall of the southern range. The entrance led through the gate, preceded by a neck, placed on the axis of the southern range.
In front of the upper castle extensive trapezoidal outer bailey was located. Along its curtain stood a coach house, stable, brewery, granaries, a bathhouse and a forge on the south-eastern side. There was also an infirmary on the outer ward. The gate was probably located from the north-eastern side. Probably on the eastern side of the castle there was a second outer bailey with a completely timber construction.
The latest stage of the medieval expansion of the castle from the late fourteenth or early fifteenth century was associated with the construction of buildings in the upper castle zwinger area. Relics of the house with the stove were found under the dansker, while the elements of armor found in it may indicate the economic function of the building. Also, sections of the eastern and southern zwinger on the eastern side of the gate were built tightly. Some of the houses situated there had basements, while some were shallow, which indicates their wooden or half-timbered construction.
To this day, the south range with the chapel, the facade in almost full height, two corner towers, adjacent to it, part of the eastern range, and relics of the walls of the remaining ranges and cellars have survived. Nearly all lower parts of the southern and western walls have been preserved. Castle ruins are available to visitors. It is possible to enter both corner towers, which offer a wide view of the area. In the basement there are exhibitions, among others models of medieval buildings and torture tools.
Leksykon zamków w Polsce, L.Kajzer, S.Kołodziejski, J.Salm, Warszawa 2003.
Torbus T., Zamki konwentualne państwa krzyżackiego w Prusach, Gdańsk 2014.
Wasik B., Budownictwo zamkowe na ziemi chełmińskiej od XIII do XV wieku, Toruń 2016.