The origins of the defense establishment in Leczyca are not clearly explained. The first castle of the XI century has not been located, the remnants of the later, which operated in the twelfth and thirteenth centuries, located in the meadows near the current podłęczyckiego Tumu. Jan Dlugosz wrote about this castle "ancient" already in the power struggle between the sons of Władysław Herman: Boleslaw, called later Krzywoustym, and his half-brother Zbigniew. Casimir the convened here in 1180. Highest dignitaries of Polish descent, which made ​​a number of reforms. At the congress that were taken into the care of the poor, proclaiming that the church is subject to curse whoever makes them harm.

About half of the thirteenth century, Konrad Mazowiecki probably erected a new, broader city near the mouth of Wolicy to Bzury. Transfer Le.czyca on the currently occupied area occurred in 1267 or the location of the city, or after its destruction. It is known that Le.czyca in the second half of the thirteenth century, was destroyed several times. In 1331, the Teutonic Knights destroyed the town and besieged the castle. Ladislaus the Short missed the time of the rescue and the castle was conquered and destroyed. There has been rebuilt on the former site.

The present castle was probably built in the years 1357-1370 was built by King Casimir the Great, after he joined the principality Łęczyca the boundaries of their country. At the same time strengthened the fortifications entire city, shutting them in the shape of a square with rounded corners. Castle turned in a string of city walls occupied the south-eastern corner, and was separated from the city wall and moat fed with water from Bzury.

It is located on an artificial embankment rising to 5 meters above the surface of the surrounding area. The castle has a plan similar to a rectangle slightly the broken sides, all built of brick in the system originally Polish, but now little was left of the original face. The perimeter walls have a height of at least 10 meters, but do not know how they were surmounted.

From the city by a moat flipped drawbridge leading to the quadrangular gate tower at the west wall of the castle. This tower was about 10-meter side, passing under the gatehouse was a room prison for commoners, the passing - guard room with a window facing the city. In addition to the gate tower also had a wicket enabling descent towards the moat.

At the eastern section of the walls was "old house", which was something of a residential tower with a square plan with a side of 15 meters. On each of the three levels of "old house" there were three rooms. Of the rest of the building stand it much stronger walls and a basement, and the second floor probably existed entering the perimeter walls of the castle and city walls, where a special walkway led at least to the Dominican church in the north-eastern corner of the city.

In the south-eastern corner of the peripheral walls built with two storeys building housing, among others, "the great chamber" and the Gothic hall and armory. The destruction of the castle area of nineteenth and twentieth century did not permit the assessment of its size and layout. Between this building and the "old house" existed jednokondygnacjowa "great hall" with dimensions of 8 to 6 meters and a height of 4 meters. In the south-west corner stood a huge tower built on a square plan with a side of about 10 meters, passing above the octagon. The original height of the tower is not known, but are curious cellars, which have up to three storeys. These tunnels meet as a prison from which there was only one escape - in the eighteenth century. The only entrance to the tower was located from the porch sentry on the walls of the peripheral. The castle had another, smaller turret. It was built at the southern wall and meets the economic role. Other farm buildings existing in the castle courtyard after a fire przygródka were transferred to its territory outside the walls of the castles.

In 1406 years the city from the castle were destroyed and burned by the Teutonic Knights, but already in 1409 Wladyslaw Jagiello convened here against the parliament, of which must be made that the castle itself does not hurt too seriously and has been renovated. After the Battle of Grunwald king settled in Le.czyca part of the Teutonic prisoners.

Diets were held here several times: in 1420, 1448, 1454 and 1462 years. Shortly after the last congress buildings have fire and the castle remained in partial ruins for the next 100 years.

In the years 1563-1565 on the initiative of Castellan sieradzki and łęczycki, royal treasurer John Lutomierski renovated and expanded Łęczyca stronghold. The scale of the project provides an inventory of 1564, which sets out the scope of the work carried out, and the amount you spent on expansion - 3000 zł. During the extension was built partially preserved today czterokondygnacjowy "new house" between the gate tower and the north wall of the castle. Same gate tower has been restored and enriched with dostawioną staircase to the south wall. Extended with its one-storey height equating the "new home" and covered the whole one roof.

Other buildings castle has also been completely renovated and refurbished. In the "old house" mentioned foundations, extended with one floor and brought out on the porches on the wall perimeter. "Mud" has been restored and put in the new vault. The building of "great chamber" and "armory" was also raised by one floor. Extended with the damaged tower, covered with new helmet and crowned with battlements. The whole circuit of the walls was strengthened, and the whole superstructure of his top porch fulfilling the functions of both defense and communication, as all castle buildings have input on the porch.

In the mid-seventeenth century, the population Le.czyca plague struck and the city reached a fire. Soon after, in 1655 weakened the city with the castle occupied by the Swedes. The first attempt to rebound the fortress by troops Stefan Czarnecki failed before reaching the army under King Jan Kazimierz Swedish forced the crew to surrender. The castle, however, was severely hit during these assaults, and no one took care of its refurbishment. Swedish war in 1703 deepened the destruction and the castle, though partially used, gradually changed into disrepair.

In the seventies years of the eighteenth century still secured walls and tower, and later the Prussian authorities in connection with the plans of the city fortification also intend to rebuild the castle, but after the occupation by the Austrians Le.czyca plans were not realized. In the nineteenth century, many people Le.czyca to extract from the ruins of a building material, fortunately after the transfer of the castle to the city authorities this practice was discontinued. The castle experienced yet deployed military barracks, but no work has not been carried out, not to mention securing weathered walls.

After World War II, interest has been rebuilding this important in the history of Polish object. Found a place here Regional Museum, and then rebuilt the buildings located on the west wall, a tower, gate tower and the "new home".

Legend has it that in the dungeons of the castle tower princes Łęczyca hidden treasures, which still guards the devil Borut.