On only two occasions was Sveaborg involved in military action. The fortress was surrendered to the Russians after a negotiated settlement to end the Finnish War in 1808 and Finland was annexed by the Russian Empire and made an autonomous Grand Duchy. In the summer of 1855 during the Crimean War, English and French warships

bombarded the fortress heavily for 46 hours. The range of the cannons in Sveaborg was not sufficient to return fire and the garrison was powerless to defend itself. The fortress was damaged but, rather than disembark and attack, the enemy sailed away.