...The paper aims to show how one of the largest complexes of Radziwill estates, composed of the Principality of Niasvizh and the County of Mir, was acquired between 1565 and 1616 by Prince Nicholas Christopher, nicknamed the Orphan, Radziwill. Before attempting this, it may be useful to review briefly the general development of large-scale land ownership in the Grand Duchy of Lithuania, and the earlier history of the Radziwill family...