Task: Question Generation
Input (English): Passage: The Russians advance into the Polish-Lithuanian Commonwealth led to the kingdom of Sweden invading Poland in 1655 under King Charles X. Afanasy Ordin-Nashchokin then opened negotiations with the Poles and signed an armistice, Truce of Vilna, on 2 November. After that, Russian forces marched on Swedish Livonia and besieged Riga in the Russo-Swedish War of 1656-1658, a theater of the Second Northern War. Khmelnytsky was not against this temporary truce and supported the Tsar though he warned him of Polish furtiveness. Ivan Vyhovsky, the newly elected hetman in 1657 upon the death of Khmelnytsky, allied himself with the Poles in Sept. 1658, creating the Grand Duchy of Ruthenia.  However, the Cossacks were also beset with the start of a civil war with this Commonwealth treaty and a new Treaty of Pereyaslav with Russia in 1659. The Tsar concluded with Sweden the advantageous Treaty of Valiersar, which allowed him to resume hostilities against the Poles in October 1658, capturing Wincenty Gosiewski at the Battle of Werki.  In the north, Sapieha's attempt to blockade Vilnius was checked by Prince Yury Dolgorukov  on October 11. In the south, the Ukrainian Vyhovsky failed to wrest Kiev from Sheremetev's control where Russians kept their garrison. In July 1659, however, Vyhovsky and his Crimean Tatar allies inflicted a heavy defeat upon Trubetskoy's army, then besieging Konotop.
Output (English): What country did King Charles X rule over in 1655?