The oldest mention about Sieradz comes from 1136 from the Gniezno Bull, in which it was noted that it was the seat of the castellany with the market and customs chamber. Originally, on the site of a later castle, an earth and timber hillfort functioned, dating back, according to archaeological discoveries, to the beginning of the 11th century. When Sieradz became the prince’s seat in the 13th century, Leszek the Black renovated the old stronghold, strengthened the ramparts and erected a brick rotunda with a separate chancel. After Leszek, these lands were ruled by Władysław Łokietek, who was forced to capitulate twice in Sieradz in the face of the prevailing Czech forces. In the years 1327-1339, the noble prince of Sieradz was the nephew of Łokietek, Przemysł, during which the wooden stronghold burnt down due to the Teutonic invasion in 1331. After this event, king Kazimierz the Great erected a brick castle, but it did not happen faster than in 1357.
In the 15th century the castle was rebuilt, full form was received only in the times of king Władysław Jagiełło. Under the Jagiellonian rule, the fortress served as an important political center, where congresses were held to decide the successors of the throne: in 1432 Władysław III Warneńczyk and in 1445 Kazimierz Jagiellończyk. Royal privileges were also granted here, and the truces were approved. After the death of king Kazimierz, Sieradz lost the function of the royal seat to Piotrków, becoming the seat of the royal starosts. In the era of one of them, Jan Spytek Tarnowski, in the first half of the 16th century, a renaissance reconstruction of the castle was carried out. Among other things, it was then reinforced by the outer circumference of the fortifications, and the rotunda after the collapse of the vault was rebuilt and intended for residential purposes. Another reconstruction of the castle took place after the fire in 1578.
During the Swedish Deluge in 1655 castle was destroyed by the Swedes. It was rebuilt around 1670, but its condition was systematically deteriorating. Demolition was conducted around 1800.
The castle was built of brick on stone foundations on a plan similar to a circle about 71×60 meters. It consisted of a 2.6-3 meter thick perimeter wall, four-sided gatehouse situated in front of the northern line of the walls, the main tower standing next to the gate, a residential house located near the walls in the southern part of the castle and timber economic buildings. Among the latter, at the western curtain of the wall, the 14th and 15th century castle kitchen was discovered. It was a timber building about 6 meters long. After 1533, the kitchen was pulled down and moved more to the north.
The height of the defensive wall, known from sixteenth-century inventory, was 11.8 meters. Its crown ran a porch for the defenders and battlements, and in the ground of the eastern curtain there was a channel that drained water from the courtyard. The whole castle was surrounded by an moat of a dozen or so meters wide.
The main tower flanked the entrance gate to the castle and served as a bergfried. It was erected on an octagonal projection with a diameter of about 10 meters and a wall thickness of 2.35 meters, that is, such as the thickness of perimeter walls. The total height of the tower was almost 16 meters, so its crown protruded only 4 meters above the battlements of the defensive walls. The entrance to it was located at a height of 7 meters above the level of the courtyard (probably accessible by ladder), and the interior was divided into four floors. The lowest, dark and stiffer storey probably served as a prison.
The gatehouse located at a distance of about 9 meters from the bergfried tower, was a three-story building, perhaps with the top floor in timber construction. Above the gateway, there was a chamber lit with two windows, with a niche cabinet in the thickness of the wall.
The residential building at the southern curtain was 46 meters long, 10.6 meters wide, 11.8 meters high and slightly thinner walls on the north side than the perimeter walls (2 meters). On the ground floor, it had three rooms, of which the middle one was the largest (9×17.5 meters), the western one was not much smaller (10×16 meters) and the eastern smallest (7.5×8 meters). In the central chamber, relics of the pillar supporting the vault or the ceiling were discovered, probably there were three such columns originally in the room. In the 16th century, this room served as a great hall, the eastern chamber had a treasury function, and the western one was used as an archive and an armory. The basement floor was divided into four chambers, of which the easternmost was a prison. The others were mainly food, barrels of beer, hunting and fishing accessories stores. The floor of the building was divided into so-called a higher hall, a western chamber (warmed with a stove and equipped with a latrine) adjacent to it and an eastern chamber. The communication between the floors was provided by an external, timber porch by the north façade. It was possible not only to move along the house, but also to go to the porch in the crown of the defensive walls. In addition, the eastern chamber was connected by a brick and roofed passage to the chapel.
To the east of the main house there was a rotunda of Leszek the Black from the 13th century, functioning later in the Middle Ages as the castles chapel. It was a two-part building consisting of a west nave founded on a circular plan (10.2 meters in diameter) and set on a stone foundation and an eastern apse (5×5,9 meters), which was three-side ended from the east and placed also on a stone foundation. The thickness of the nave wall ranged from 2.20 to 2.40 meters, while the thickness of the apse wall was about 1 meter. The external and internal face of the rotunda was made of brick in the monk bond. Rotunda was a two-story building, probably covered with wall polychromes in the times of Władysław Jegiełło. As mentioned above, the upper floor was connected by the passage to the eastern chamber of the main house.
In the first half of the 16th century (1537-1541) at the base of the embankment on which the castle stood, an external, timber ring of fortifications was erected. It consisted of a shingled fence with shooting holes and a covered sidewalk for defenders. The ring was reinforced with five towers. More or less in this period also was erected the so-called courthouse in the north-eastern part of courtyard. It was a wooden, two-storey building (9×25-30 meters) added to the defensive wall. Its ground floor served as a warehouse and had an economic function (pantry, chicken coop, store), and the floor served as a courtroom, accessible through the outer stairs and porch. The last building added in the first half of the sixteenth century was a bakery at the eastern section of the wall and a house for service at the western curtain. The bakery at first was a building constituting a dwellings for the castle guards, and the function changed in the second half of the sixteenth century. It was a one-storey wooden building (16-19×6.5 meters) with a centrally located entry hall, a room with a stove on the south side and rooms from the north. The house for the servants had two floors containing a total of eight rooms, each lit by a separate window.
Castle has not survived to our times. Admission to the castle area is free. In the District Museum in Sieradz, you can see movable artefacts found during archaeological works in the area of the castle, in the form of ornaments, tools and fragments of weapons.
Leksykon zamków w Polsce, L.Kajzer, S.Kołodziejski, J.Salm, Warszawa 2003.
Olszacki T., Zamek królewski w Sieradzu, Sieradz 2013.
Widawski J., Miejskie mury obronne w państwie polskim do początku XV wieku, Warszawa 1973.
Website zamkilodzkie.pl, Sieradz, zamek królewski.