Russia, having recovered to a certain extent from the Time of Troubles, agreed with the assessment that the Commonwealth would be weakened by the death of its king, and unilaterally attacked without waiting for the Swedes and the Ottomans. Russia's aim was to gain control of Smolensk, which it had ceded to the Commonwealth in 1618 at the Truce of Deulino, ending the last Russo-Polish War. Smolensk was the capital of the Commonwealth's Smoleńsk Voivodeship, but it had often been contested, and it changed hands many times during the 15th, 16th and 17th centuries (from the days of the Muscovite–Lithuanian Wars). A major supporter of the war was the Tsar's father, Patriarch Filaret, who represented the anti-Polish camp at court. Inspired by the Zemsky Sobor's (Russian parliament's) call for vengeance and reclamation of lost lands, the Russian army sallied west.