ENThe Lithuanian Chancellor, Lev Sapieha, effectively controlled the policy of Polish-Lithuanian Commonwealth towards the Muscovite state from the beginning of his career. This was especially visible during the Time of Troubles, when at the expense of the interests of Sigismund III and the Tsar-elect, prince Wladyslaw, he reinforced the position of the Grand Duchy of Lithuania within the Polish-Lithuanian Commonwealth and muscovite policy. The article, based on unused and unknown before source documents, outlines Sapieha’s activity in the final stage of the Time of Troubles - the Moscow expedition of Prince Wladyslaw in 1617-1618.