In June 1610, De la Gardie and Prince Dmitry Shuisky – an uncle and rival of Skopin-Shuisky (who was poisoned at the behest of his uncle) – departed from Moscow, in order to lift the Polish-Lithuanian Siege of Smolensk. The campaign ended with most of De la Gardie's forces defecting to the Polish hetman Stanisław Żółkiewski at the Battle of Klushino, causing a defeat to De la Gardie's alliance on 4 June 1610. After this, De la Gardie's remaining army returned to Vyborg during that summer.