On 31 January 1610 Sigismund received a delegation of boyars opposed to Shuyski, who asked Władysław to become the tsar. On 24 February Sigismund sent them a letter in which he agreed to do so, but only when Moscow was at peace. The combined Russian and Swedish armies were defeated on 4 July 1610 at the battle of Klushino. After the news of Klushino spread, support for Tsar Shuyski almost completely evaporated. Żółkiewski soon convinced the Russian units at Tsaryovo, which were much stronger than the ones at Kłuszyn, to capitulate and to swear an oath of loyalty to Władysław.

In August 1610 many Russian boyars accepted that Sigismund III was victorious and that Władysław would become the next tsar if he converted to Eastern Orthodoxy. After a few skirmishes, the pro-Polish faction gained dominance, and the Poles were allowed into Moscow on 8 October. The boyars opened Moscow's gates to the Polish troops and asked Żółkiewski to protect them from anarchy. The Moscow Kremlin was then garrisoned by Polish troops commanded by Aleksander Gosiewski.