In an attempt to take advantage of the confusion expected after the death of the Polish king, Tsar Michael I of Russia invaded the Commonwealth. A Muscovite army crossed the Commonwealth eastern frontier in October 1632 and laid siege to Smolensk (which was ceded to Poland by Russia in 1618, at the end of the Dymitriad wars). In the war against Russia in 1632–1634 (the Smolensk War), Władysław broke the siege in September 1633 and then in turn surrounded the Russian army under Mikhail Shein, which was then forced to surrender on 1 March 1634.