The palace in Jadwisin, also known as the Radziwiłł palace, is a valuable architectural monument located picturesquely on a high escarpment above the Narew River. Its construction was completed in 1898 and the design was the responsibility of French architect François Arveuf, who gave the building a style reminiscent of the French Renaissance.
The palace is distinguished by its asymmetrical layout of volumes, faced with red-brown ceramic tiles that contrast with the lush greenery of the park, and the tower in the front elevation. Above the main entrance is the monogram of the first owners, Jadwiga and Maciej Radziwill, and on the river side of the risalit are the family coats of arms “Ślepowron” Krasiński and “Trąb” Radziwill. Near the palace, stylish outbuildings with a coach house and stables were erected. Around 1900, a landscape park was arranged around the palace, which after almost 100 years was transformed into the “Jadwisin” nature reserve, covering 93 hectares of the former Serock Forest.
Radziwiłł Palace in the interwar period. Source: Polona
The palace and zegrzyn estate were owned by the Radziwill family until 1939. The last owners before the Second World War were Konstanty Mikołaj Radziwiłł and his wife Maria née Żółtowska. Konstanty Radziwiłł, in the rank of reserve second lieutenant, took part in the defensive war of 1939, fighting as an observer in the 13th Air Squadron. After the Nazi invasion, the Radziwiłłs had to leave the palace and settled in a forester’s lodge near Arciechów.

During the Second World War, Konstanty Radziwiłł, using the pseudonym “Korab”, became involved in underground activity as an officer-commander of the Third Battalion in Nieporęt. In August 1944, after fighting in the uprising, he was arrested by the Germans and probably executed on 14 September 1944 in Zegrze. His remains were accidentally found in 1969, and his identification was made possible by a scapular medal with the image of St John Bosco, which he had received from Primate August Hlond.

After World War II, the Jadwisin estate was parcelled out and the palace was handed over to the Ministry of Education. In 1960, it was taken over by the Chancellery of the Prime Minister. Since then, the closely guarded residence has become a place of rest for communist activists, but also a training place for party activists. After the political transformation, the palace opened up to other guests and ran a commercial hotel and catering business. In 2016, the Radziwill family reclaimed the residence, but soon sold it.
Currently, the palace and the “Jadwisin” reserve are off-limits to tourists. Despite this, the Radziwill palace remains an important testimony to history and architecture, attracting the attention of both historians and lovers of beautiful historic residences.
Source: historia.serock.pl, jezioro.zegrzynskie.pl
Read also: Architecture | Monument | Palace | Architecture in Poland | Villas and residences