ENThe study is devoted to the peculiarities of relations in the multicultural community of the so-called Neuburg estate, the legacy of the Evangelical line of the Radziwill family of Biržai in the Grand Duchy of Lithuania and Podlasie. Amalgamated after the death in 1655 of the Grand Hetman of Lithuania Janusz Radziwill by his cousin Boguslaw, the extensive estate was inherited by his daughter and then came under the protection of the widower of the Prince Palatine of Neuburg, Charles Philip Wittelsbach. In 1730, it was handed over by him to the Catholic Radziwills of Nyasvizh, but the measures taken earlier by the evangelical administrators of the estate resulted in a relative stabilisation of relations in the multicultural social space of the Neuburg estate. Relations in the various types of “cultural borderlands” that cut across this space, social, ethnic, linguistic, religious and confessional, constituted at the turn of the 18th century a peculiar phenomenon in the Sarmatian-Catholic-dominated cultural model of the society of the Polish-Lithuanian Commonwealth.