After court proceedings, the counts of Pálffy, the brothers Josef and Petr, gained Slavkov in 1923, however their property was confiscated in 1945 by decree no. 12 of president Beneš. The manor Slavkov u Brna thus became the State's property and remained State property until 1996, when it was registered as the property of the town Slavkov u Brna.
At the turn of the 12th and 13th centuries, this originally monarch's territory, on which the contemporary town of Slavkov u Brna is located, was lent by the margrave Vladislav Jindřich to the Order of the German Knighthood. In their possession, Slavkov (Naussedlicz, from this corruption of the name probably also arose the German name of the town – Austerlitz) is mentioned in writing for the first time in 1237. The Slavkov commandery gradually became one of the most important commanderies of the Order in the Czech lands. In 1411, king Václav IV took over, including some other settlements, the Slavkov commandery and the property continued to be lent as a royal fief – the German Knights only held the vicarage in the town.
During the course of the 15th century, a number of families took their turns in Slavkov. At the beginning of the 16th century Oldřich from Kounice is mentioned, the first member of the family that held Slavkov for more than four centuries. Under Oldřich's son, also called Oldřich, the Slavkov castle, at the end of the 16th century, was gradually rebuilt into a Renaissance manor where in 1608 the nobility, revolting against the emperor Rudolf II, had their debates.
After their father's death (1617), Slavkov was held by his sons, Bedřich and Karel. However, due to their participation in the uprising against the emperor, the property was confiscated from both brothers and the Slavkov manor was given to their youngest step-brother Lev Vilém, who became the founder of the Moravian branch of the Kounic family. He took over Slavkov in 1632.
After Lev Vilém died in 1655, the property was held by his son Dominik Ondřej, who at the end of the 17th century started the reconstruction of the Renaissance Slavkov manor into a stately Baroque manor. After Dominik Ondřej died in 1705, Slavkov became the property of his younger son Maxmilián Oldřich, who was Moravia's regional hetman (regional leader) from 1720. He also continued in the reconstruction of the Slavkov manor.
In 1746 he was succeeded by his son Václav Antonín Dominik (1711-1794), a leading figure in Austrian diplomacy for almost the entire second half of the 18th century. For his noteworthy acts, he was promoted in 1764 into the hereditary principality with the right of primogeniture. The last descendant of the Moravian branch of the Kounic family was Alois Václav, who died in 1848 in Paris.
On the basis of the family contract, Slavkov was then transferred to the Czech family branch, the most noteworthy of which was the next to last member of the family, Václav the count of Kounice, who owned the manor from 1897 until his death in 1913. Then the property was taken over by his brother Eugen, but he died in 1919 and thus the Kounic family definitively died out.