The Schmidegg family that rose to the rank of count in 1738, acquired the estate of Sárladány in 1736 and built a baroque manor house, which had already stood in 1738, as a prelude to the current mansion. The estate and their residence were sold to Count Lipót Nádasdy (1802–1873) in 1851, who wished to move the centre of his estates from Felsőlendva in Vas County to a settlement in Fejér County, which from 1859 was called Nádasdladány. To the north of the small mansion a landscape garden had already been established. The foundation of the later kitchen garden, the plant bed in front of the main façade, the granary and the predecessor of the building housing the service rooms had already been in existence also.

Based on the plans of the land-seizer’s son Ferenc Nádasdy (1842–1907) and his wife, Countess Ilona Zichy (1849–1873), a new, historicising, neo-Gothic, English Tudor-style mansion was built between 1873 and 1876, by extending the former baroque building with an L-shaped main wing. The ground floor of the new main wing was lined with public spaces, family and staff rooms were established on the first floor, the area around the old building was filled, and rooms for guests and staff members were created in the ground floor wing. Due to her unexpected death, the young countess could not live to see the completion of the mansion. Following Linzbauer’s death, Alajos Hauszmann was commissioned to design the most ornate interiors of the building, the masterpieces of our historicising mansion architecture, the Hall of Ancestors, the library, as well as the chapel.

It is known from the research of József Sisa that Nádasdy designed the exterior and interior of the building around three main themes. The ancient glory of the Nádasdy family was the first. Coats of arms referring to the ancestors and heroes of the family appeared on the busy, asymmetrical façade in several places, but they were also depicted in statues placed in the vestibule and, of course, in the portraits presented in the Hall of Ancestors. In addition, the two other topics presented were the honour and cult of the count’s deceased wife who died young and, as one of the most prestigious members of the hunting community, the owner’s hunting relics, trophies and passion for horses.
Although the furnishings and atmosphere of the mansion were reminiscent of the past, at the same time it was equipped with the most modern technical devices of the era to ensure the comfort of its inhabitants.

By the end of the 19th century, the building and its surroundings had become the centre of the estates of the formerly much larger Nádasdy family, their main rural home, the repository of their applied and fine art collections and library, and the number one base for their excellent stud. Until the Second World War, first the commissioner’s son Tamás (1870–1915) and his family, then his eldest son Ferenc (1907–1944) and his relatives lived in the mansion.