About the book: 2010 / The monograph is devoted to the study of relations between Russia and its western neighbors in those years when after the Pereyaslav Rada and the annexation of Ukraine, the Russian state made great efforts to solve the main foreign policy tasks facing it - the unification of all East Slavic lands and the conquest of access to the Baltic Sea. The work is based on extensive documentary material from various collections of the Russian State Archive of Ancient Acts.