ENThe works of Polish, Lithuanian, Belarussian researchers in the Lublin Union and the II statute of the Grand Duchy of Lithuania are analyzed in this article. The circumstances of introduction of changes in the management system of the Grand Duchy of Lithuania and their strengthening at the legislative level through the adoption of the II statute are disclosed. It is shown what political forces were interested in this and who resisted these changes. Keywords: Lithuanian statute, Lublin union, Rzeczpospolita (Polish and Lithuanian Kingdom). [From the publication]