Slavonia and Croatia belonged to the Habsburg controlled part of the Kingdom of Hungary. As a result of the Ottoman conquest, the two provinces merged into a single territorial entity, and this study discusses this process. The noble society and the public administration of Croatia and Slavonia had fewer and fewer links with the Hungarian institutions due to economic, religious and military reasons. However, in the meantime they established close relationships with the Habsburg dynasty and the Austrian hereditary provinces. The local nobility developed the idea of the independent Croatian state in the 16th–17th centuries, and thus, the territory could not reintegrate completely into the Kingdom of Hungary in the early 18th century.