Catholic Swedes, and others—in the eastern parts, particularly the Karelians—cooperating with the Orthodox Russians. Furthermore, during the first several centuries of the Swedish expansion to the traditional lands of the Finns—up to the 16th century and beyond—only the south-western parts of the area known today as Finland (then the lands of the Finns reached also beyond today's borders of the Republic of Finland) had been reached by the Swedish expansion and thus had become part of the Swedish realm. From 1323 until 1809, Finland was officially an integral part of the Swedish Realm, including first only the south-western lands inhabited by the Finns but expanding east as time went by. Finnish soldiers fought in at least 38 known wars of Sweden, all of them having something to do with either power struggles within the Swedish royal family or struggles between Sweden and other nations. Grand Duchy of Finland As a result of the so-called Finnish War of 1808–1809 Finland became an autonomous Grand Duchy of Finland in the Russian Empire until Finland's declaration of independence on December 6, 1917. During that period the Finnish army participated in the wars of Russia, such as the Crimean War—during which, in 1855, the French and the British navies attacked Finland—and the First World War. Republic of Finland From 1917 on Finland has been an independent republic. This period started with the Finnish Civil War in 1918, between the Reds (communists) and the Whites (mixed right wing, liberal and centrist groups allied against the Reds), soon after Finland's declaration of independence. The former were supported by Bolshevik Russia, and the latter by the German Empire. The Whites eventually defeated the Reds. World War II In 1939, Finland was in war against the Soviet Union during the Winter War. The war lasted 105 days. The Continuation War against the Soviet Union lasted from the summer of 1941 until the fall of 1944. In 1944 and 1945, Finland attacked German Wehrmacht forces leaving the country in the Lapland War. Post World War II Soon after the birth of the United Nations, Finnish military troops—including various types of military personnel and advisers—started participating in many UN peacekeeping operations, beginning in 1956 with the United Nations Emergency Force at the Suez Crisis. Defense strategy in Finland after World War II required tact and diplomacy. In the event of major hostilities, The Finnish Defence Forces basically needed to hold