The manor became two storeys high and more spacious, but its style became mixed with Baroque Revival, neo-Renaissance and Art Nouveau features.

[4] Rokiškis manor was first mentioned in 1499 in the privilege of Grand Duke Alexander Jagiellon of Lithuania for cutting the forest for Jurgis Stanislovaitis Astikas.

[6] After the death of Grand Duchess Helena in 1514, the Rokiškis manor was passed on to Duke Timotiejus Filipovičius Krošinskis.

By a privilege of 9 November 1547, the Grand Duke of Lithuania and King of Poland, Sigismund the Old, gave the Rokiškis manor, by right of fiefdom, to Ivanas Timotiejevičius Krošinskis and his descendants in perpetuity.

And yet, in the 18th century, Rokiškis already had a large market square, a Saika as a measure of its volume, a blacksmith's forge, a brewery and a mill.

Rokiškis flourished most at the end of the 18th century, when Ignacy Tyzenhauz (Ignotas Tyzenhauzas), a major-general in the Grand Duchy of Lithuania's army, and a participant in the Kościuszko Uprising of 1794, became the owner of the estate and made it his permanent residence.

A military officer by profession and a renowned ornithologist by hobby, a student of professor Stanislovas Jundzilas, he turned Rokiškis into a hub of science.

His ornithological collections amounted to some three thousand specimens, and books authored by him are used as a source of study for today's Lithuanian biology students.

The Duke's sister, Marija Tyzenhauzaitė- Pšezdzieckienė (Maria Przeździecki), contributed to the interior decoration of the Rokiškis church.

Her husband, the Polish historian Aleksander Przeździecki (Aleksandras Pšezdzieckis), brought to Rokiškis his family coat of arms, a silver lily with three stripes on a red field.

During his time, the original Zakopane Style dining room and the bright and high concert hall were decorated with works of fine art collected by the families who ruled the estate - the Counts Tyzenhauz and later Przeździecki.

The collection included canvases by Titian, Caravaggio, Rubens, Bruegel, Adriaen van Ostade and other famous painters of Western Europe.

On 15 June 1940, Petras Bliūdzius the curator of the museum, together with his whole family was arrested by the Soviets and deported to Siberia after he tried to save the works of art in the manor.