False Dmitry II
During Russia's Time of Troubles, Vasily IV of Russia was besieged in Moscow by the supporters of the second False Dmitry. Driven to despair by the ongoing Polish intervention, he entered into an alliance with Charles IX of Sweden, who was also waging war against Poland. The tsar promised to cede Korela Fortress to Sweden in recompense for military support against False Dmitry II and the Poles. The Swedish commander Jacob de la Gardie joined his forces with the Russian commander Mikhail Skopin-Shuisky and marched from Novgorod towards Moscow in order to relieve the tsar.