Sielce Manor in Warsaw, established between 1775 and 1786 by King Stanisław August Poniatowski, was a royal palace complex located near the Royal Łazienki Park. The estate includes a central Neoclassical palace, two outbuildings, farm structures, and an English-style garden, today known as Sielce Park. From the entire complex, mainly the palace, the outbuildings, and remnants of the garden have survived to this day, and the site was entered into the register of historical monuments in 1977. Although Sielce Manor existed as early as the 16th century, it gained prominence in the late 18th century when Poniatowski established a landscape park with a central pond there. The manor buildings appear on maps of Warsaw from 1796, confirming their earlier existence. The purpose of the manor was to support the royal treasury through agricultural production, typical of the self-sufficient estates of that era. After Poniatowski's abdication in 1795, the property passed through the hands of various owners, including Grand Duke Constantine, who, according to some researchers, was mistakenly credited as the founder of the original palace complex. In the 19th century, the manor was managed by the Administration of the Łowicz Duchy, and after 1831, it became the property of Tsar Nicholas I. In 1918, after Poland regained independence, efforts began to revitalize the complex. During the interwar period and World War II, the complex survived with minimal damage, but during the Polish People's Republic, it fell into disrepair, and the buildings were converted into apartments. After 1989, the palace gradually deteriorated, but in 2005, it underwent a thorough renovation, although the original interiors were not preserved. Currently, the manor is state-owned but not open to the public. The complex also once included a smaller eclectic-style palace, which disappeared after World War II.