Picturesquely situated on the shores of Lake Siesiki , the castle – or rather, the small castle – is an example of a Renaissance residence which, although it no longer served strictly defensive purposes, continued to employ the architectural style of medieval fortresses. In this way, the building emphasised the chivalrous nature of its owners – the Dowmont-Siesicki family – who, according to family legend, were descended from the Lithuanian Duke Gediminas.

No scholarly study has yet been written about the picturesque castle, or rather small castle, in Siesiki , but authors of historical novels are keen to set their stories within its walls, as exemplified by Wacław Gąsiorowski’s *Emilia Plater*. The castle itself, with the distinctive charm of its thick, squat walls , has become shrouded in legend, and various guidebooks contain many fanciful tales about it. First and foremost, it should be emphasised that a small defensive post must have existed on this site as early as the 15th century, during the reign of King Władysław Warneńczyk (1434–1444), the eldest son of Władysław Jagiełło. The timber-and-earth structure belonged at that time to Dowmont (Dowmunt), the ‘prince of Uciana’. It served not only as a watchtower but was also a base for hunting in the surrounding Lithuanian primeval forests, which were dense at the time.

At the beginning of the 16th century, the owner of the Siesiki estate was a descendant of Dowmont – Gabriel Dowmont – who built a stone residence on the shores of the lake by 1517. Taking their name from the village, he and his successors adopted the name Dowmont-Siesiccy, bearing the Bawola Głowa coat of arms. They were active participants in political life in the Wiłkomierz district, though they did not attain any great significance. Their most prominent representative was Kazimierz Władysław (d. 1691) – Marshal of the Lithuanian Tribunal in 1676 and Grand Master of the Kitchen to the King of Lithuania, serving as an elector to Jan III Sobieski.

In the centuries that followed, various modernisation works were carried out on the castle, and the estate remained in the hands of the Dowmont-Siesicki family until the early 18th century, when Marianna (Marcjanna), daughter of the Voivode of Mścisław, married Michał Antoni Radziwiłł (1687–1721) of the Trąby coat of arms. Following the childless deaths of her brothers Kazimierz and Stanisław, she brought the Siesiki estate into her husband’s household. Their posthumous son, Leon Radziwiłł ( 1722–1751) sold the debt-ridden estate to the Dowgiałło family of the Zadora coat of arms in 1745. The memory of the Dowmunt family , however, has survived in the names of the nearby villages: Dowmuntyszki and Dowmuntowo.

The new owner, Kazimierz Dowigiałło, rebuilt the palace, which had been destroyed by the Swedish army during the Swedish Deluge. A further restoration was carried out between 1820 and 1839 by his grandson Dominik ( 1789–1857). Among other things, he ordered the towers facing the lake to be topped with neo-Gothic battlements and the two front towers to be demolished. A Classicist-style stable and granary were also built at that time. The next owner was Stanisław Grzegorz Dowgiałło (1822–1905) . On his initiative, a Neoclassical building known as the Academy was constructed nearby in 1904, serving both guests and the educational needs of the local population. The building features two porticoes on its shorter sides.

The estate remained in the Dowgiałło family’s possession until 1940, when Oskar Jan Dowgiałło (1902–1988) and his wife Krystyna, née Jezierska, were forced to leave it. After the war, they settled in Sopot. After 1945, the palace housed a school, then the offices of a collective farm and flats for its workers. From 1972, the building stood abandoned. In 1999, renovation work began, which was completed a few years ago, with a branch of the museum in Wiłkomierz being housed in the palace.

The castle was built on the shores of a lake and surrounded on three sides by a moat. It is a two-storey structure on an elongated rectangular plan, originally flanked at each of its four corners by squat towers, each one storey higher than the main body of the building. Only two of them have survived, on the lake side – one circular in plan and the other square. This suggests that they were not built at the same time. In the decades that followed, a terrace was built between the towers, offering views of the picturesque surroundings as well as the owner’s estates stretching to the horizon. The building is crowned by a high roof. The structure, with its towers of varied floor plans, adorned with arcades, panelling and a variety of alternating openings, was notably picturesque. The castle in Siesiki can be compared to similar watchtowers in Rokanciszki or Narviliszki in Lithuania.

The castle in Siesiki has preserved old fireplaces and vaults dating from the 16th to the 18th centuries, as well as some of the polychrome decoration and the brick floor. Some of the rooms were covered with ceilings. The castle – a residential mansion – was surrounded by a 3-hectare park, the remains of which are still visible today.