On November 14 (27), 1917, soon after the October coup in Petrograd, the Seim (Parliament) of Finland declared the country's independence from Russia and appointed a Government headed by Pehr Evind Svinhufvud. On November 23 (December 6), 1917, the Seim adopted the Finnish Declaration of Independence titled “To the Finnish Nation”. On December 18 (31), 1917, the Council of People’s Commissars of the Russian SFSR issued a Decree recognizing Finland's independence. On the same date, the Åland Islands proclaimed being part of Sweden. Later on, Finland's independence was recognized by Sweden, France, Germany, Norway, and Denmark.

 

On the night of January 15 (28), 1918, in Helsingfors (Helsinki) a social upheaval took place. The Executive Committee of the Finnish Workers formed by the radical wing of the Social Democratic Party of Finland seized power over the southern part of the country. Svinhufvud’s Government fled northward to the city of Vaasa. As opposed to the Red Finns, the supporters of the Vaasa Senate were called the White Finns. Carl Gustaf Mannerheim became the Commander-in-Chief of the Vaasa Senate military forces and started to form the Finnish Army.

 

On March 7, 1918, the Vaasa Senate concluded a peace treaty with Germany. German troops led by General von der Goltz have invaded the country and helped the Whites to win the Civil War in Finland by mid-May 1918.

 

On May 18, 1918, the Senate elected Pehr Svinhufvud the State Regent of Finland. A new pro-German Government was established. In August 1918, the royalist Seim proposed to establish a kingdom. On October 9, 1918, Frederick Charles of Hesse was elected the King of Finland, though he has never been crowned as Germany lost World War I and the political situation in Europe changed dramatically. The pro-German Senate was dissolved and Pehr Svinhufvud resigned. On December 12, 1918, Carl Gustaf Mannerheim was elected the new State Regent. On July 17, 1919, he signed the Constitution Act adopted by the Senate. As a result, Finland became the Presidential Republic.

 

Aleksander Kolchak and Nikolay Yudenich, leaders of the White movement in Russia, approached Carl Mannerheim asking him to support their military coup against the Soviet power in Russia. However, they have never guaranteed they would recognize Finland’s independence, so Mannerheim refused his support.

 

In 1918–1920, Finland occupied some of the territories in Karelia, Pechenga, and the Olonets Governorate. In April of 1919, the Olonets Volunteer Army of the White Finns took control over the Southern Karelia, part of the Eastern Karelia, and approached Petrozavodsk. In July of 1919, as a result of the Vidlitsa Operation by the Workers’ and Peasants’ Red Army, the Finnish troops were flung back the to state border.

 

On October 14, 1920, the Russian SFSR and Finland signed the Treaty of Tartu. As a result, Finland received Pechenga region (Petsamo), the western part of the Rybachy Peninsula, and most of the Sredny Peninsula. While Russia received back the Porosozero and Repola areas that were earlier occupied by Finland. In 1921, the League of Nations determined that the Åland Islands should remain under the Finnish sovereignty, having though wide autonomy.