The Polish army commenced a siege of Smolensk and the Russo-Swedish relief expedition was defeated in 1610 by Hetman Żółkiewski at the Battle of Klushino. The victory strengthened the position of the compromise-oriented faction of Russian boyars, which had already been interested in offering the Moscow throne to Władysław Vasa, son of Sigismund III. Fyodor Nikitich Romanov, the Patriarch of Moscow, was one of the leaders of the boyars. Under arrangements negotiated by Żółkiewski, the boyars deposed Tsar Vasili and accepted Władysław in return for peace, no annexation of Russia into the Commonwealth, the Prince's conversion to the Orthodox religion, and privileges, including exclusive rights to high offices in the Tsardom granted to the Russian nobility. After the agreement was signed and Władysław declared tsar, the Commonwealth forces entered the Kremlin (1610).