In the end, Sigismund did not succeed in becoming tsar or in securing the throne for Władysław, but he was able to expand the Commonwealth's territory. During his reign Poland was the largest and most populous country in Europe. On 11 December 1618 the Truce of Deulino,:567 which concluded the Dimitriad's war, gave the Commonwealth control over some of the conquered territories, including the territories of Chernigov and Severia  and the city of Smolensk, and proclaimed a 15-year truce. Władysław refused to relinquish his claim to the Russian throne, even though Sigismund had already done so. While the Commonwealth gained some territories in the east, in terms of finance and lives it was a very costly victory. In 1632 the Truce of Deulino expired, and hostilities immediately resumed in the course of a conflict known as the Smolensk War.:587 This time the war was started by the Russians, who tried to exploit the suspected weakness of the Commonwealth after the unexpected death of Sigismund III.:587 However, they failed to regain Smolensk. Mikhail Shein surrendered to Władysław IV on 1 March 1634, and the Russians accepted the Treaty of Polyanovka in May 1634.:587 The Russians had to pay 20,000 rubles to the Commonwealth, but Władysław relinquished his claim to the Russian throne:587 and recognized Michael as the legitimate tsar of Russia, also returning the Russian royal insignia.
What did Sigismund not fail at?
expand the Commonwealth's territory