The Treaty of Tartu (; ; ) was signed on 14 October 1920 between Finland and Soviet Russia after negotiations that lasted nearly five months. The treaty confirmed the border between Finland and Soviet Russia after the Finnish Civil War and Finnish volunteer expeditions in Russian East Karelia that resulted in annexation of several Russian districts.
The treaty was signed in Tartu, Estonia, at the building of the Estonian Students' Society. Ratifications of the treaty were exchanged in Moscow on 31 December 1920. The treaty was registered in the League of Nations Treaty Series on 5 March 1921.
Political background
This turbulent time in Finnish and Russian politics influenced the events that led to the Treaty of Tartu. Prior to the Treaty of Tartu, Finnish political parties shifted their sovereign policies several times. In early 1917, the conservative party was split into two factions: The Old Finns and the Young Finns. The Old Finns wanted to keep ties to St. Petersburg close and argued against an independent Finland, hoping not to agitate the Russian monarchy and further limit Finnish autonomy. The Young Finns differed in this regard as they promoted the idea of an independent Finland. The third major Finnish party were the leftist social-democrats. These social democrats also wanted to see a free and independent Finland.
All of this changed in the matter of a short few months when the Bolsheviks took control of the country during the Bolshevik Revolution. The Bolsheviks became an ally to the Finnish social democrats as they shared common ideological ground. This changed the stance of the social democrats, leading them to become pro-Russian. Meanwhile, the Old Finns, in disagreement with the Bolshevik policies became pro-independence. During the November 1917 election the coalition representing the pro-independence parties won the cabinet election and immediately moved to make Finland an independent nation with the Finnish Declaration of Independence. As the Bolshevik ideology formally subscribed to each people's right for self-determination and condemned any form of imperialism, Lenin saw the opportunity to promote his public support for the Finnish declaration as a showpiece of benevolence of the new Soviet system.
However, the move for independence, Soviet support and general uncertainty and unrest in the society encouraged the militant left to attempt to duplicate the success of Russia's recent revolution, and soon after, the Finnish Civil War began. In the war the revolutionary socialist militia known as the Finnish Red Army clashed against the Finnish White forces, which were loyal to the legal (non-socialist) government. The government's forces, assisted by a division of regular German forces and Swedish volunteers, pushed back the Red troops that had initially controlled the industrial southern provinces and within some months, won the war. The border question between Russia and Finland remained unsettled after the war. Around 1,400-1,650 people died in the ranks of the Red troops, while between 7,000 and 10,000 people died within the White ones. In total, 37,000-38,500 people died as a result of the Civil War, and 76,000 prisoners - of which 100 were executed - were captured by the Whites in cooperation with the German forces. Casualties of Finnish Civil War were according to a Finnish Government project: Died in battle: "whites" 3414, "reds" 5199; Missing: whites 46, reds 1767; Executed: whites 1424, reds 7370; Died in prison camps: whites 4, reds 11652 - total deaths 36640.