From 1788 to 1790, Russia fought a war against Sweden, a conflict instigated by Catherine's cousin, King Gustav III of Sweden, who expected to simply overtake the Russian armies still engaged in war against the Ottoman Turks, and hoped to strike Saint Petersburg directly. But Russia's Baltic Fleet checked the Royal Swedish navy in a tied battle of Hogland (July 1788), and the Swedish army failed to advance. Denmark declared war on Sweden in 1788 (the Theatre War). After the decisive defeat of the Russian fleet at the Battle of Svensksund in 1790, the parties signed the Treaty of Värälä (14 August 1790), returning all conquered territories to their respective owners and confirming the Treaty of Åbo. Russia was to stop any involvement in internal affairs of Sweden. Large sums were paid to Gustav III. Peace ensued for 20 years in spite of the assassination of Gustav III in 1792.