Shortly before his death in 1924, the childless count willed the castle, along with an extensive art collection and the Kórnik Arboretum to the Polish state.

The southern side is dominated by a chaitya arch, which was probably modelled on the Royal Pavilion in Brighton and the Islamic architecture of India.

Among the most significant works in the library are the original manuscript of Adam Mickiewicz's Dziady (Part III) and Napoleon's hand-written romantic novella Clisson et Eugénie.

In the room below the tower, there are ethnographic and natural collections on display brought from Australia and Oceania by Count Władysław Zamoyski who inherited the estate from his maternal uncle, Jan Kanty, in 1881.

[5] During the German occupation of Poland (World War II), in 1939–1940, a secret printing house of the Polish resistance movement was located in the castle.