This article discusses two successive confederations established by the clients and employees of Janusz Ostrogski. They functioned just after the death of their patron, mainly within the Ostrogski Fee Tail. The fi rst, founded in 1620, was concerned with the property claims of Ostrogski’s most trusted servants and clients during the settlement of his estate. The second exemplifi ed the political demands of the landed nobility whose domains fell within the Ostrogski Fee Tail. Both of these played an important role in shaping the legal and organisational framework for estates.