The Winter War was a war between the Soviet Union and Finland. It began with a Soviet invasion of Finland on 30 November 1939, three months after the outbreak of World War II, and ended three and a half months later with the Moscow Peace Treaty on 13 March 1940. Despite superior military strength, especially in tanks and aircraft, the Soviet Union suffered severe losses and initially made little headway. The League of Nations deemed the attack illegal and expelled the Soviet Union from its organization.
The 6th SS Mountain Division Nord was a World War II mountain infantry division of the Waffen-SS, the military wing of the German Nazi Party, primarily consisting of ethnic Germans along with some Norwegian and Swiss volunteers. It was the only Waffen-SS division to operate in the Arctic Circle.
The Estonian War of Independence, also known as the Estonian Liberation War, was a defensive campaign of the Estonian Army and its allies, most notably the United Kingdom, against the Soviet Russian westward offensive of 1918–1919 and the 1919 aggression of the pro–German Baltische Landeswehr. The campaign was the struggle of the newly established democratic state of Estonia for independence in the aftermath of World War I. It resulted in a victory for Estonia and was concluded in the 1920 Treaty of Tartu.
Finland participated in the Second World War initially in a defensive war against the Soviet Union, followed by another, this time offensive, war against the Soviet Union acting in concert with Nazi Germany and then finally fighting alongside the Allies against Germany.
The Battle of Narva was a World War II military campaign, lasting from 2 February to 10 August 1944, in which the German Army Detachment "Narwa" and the Soviet Leningrad Front fought for possession of the strategically important Narva Isthmus.
The Republic of Kirjasalo, commonly known as the Republic of North Ingria was a short-lived unrecognized state from 9 July 1919 to 5/6 December 1920. Kirjasalo was located in the southern part of the Karelian Isthmus, specifically in Kirjasalo in Lempaala.
The Baltic Sea campaigns were conducted by Axis and Allied naval forces in the Baltic Sea, the Gulf of Bothnia, the Gulf of Finland and the connected lakes Ladoga and Onega on the Eastern Front of World War II. After early fighting between Polish and German forces, the main combatants were the Kriegsmarine and the Soviet Navy, with Finland supporting the Germans until 1944 and the Soviets thereafter. The Swedish Navy and merchant fleet played important roles, and the British Royal Navy planned Operation Catherine for control of the Baltic Sea and its exit choke point into the North Sea.
The military history of Finland consists of hundreds of years of armed actions in the territory encompassing modern Finland.
The Latvian War of Independence, sometimes called Latvia's freedom battles or the Latvian War of Liberation, was a series of military conflicts in Latvia between 5 December 1918, after the newly proclaimed Republic of Latvia was invaded by Soviet Russia, and the signing of the Latvian-Soviet Riga Peace Treaty on 11 August 1920.
Infantry Regiment 200 or soomepoisid was a unit in the Finnish army during World War II made up mostly of Estonian volunteers, who preferred to fight against the Soviet Union in the ranks of the Finnish army instead of the armed forces of Germany.
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.
Estonia declared neutrality at the outbreak of World War II (1939–1945), but the country was repeatedly contested, invaded and occupied, first by the Soviet Union in 1940, then by Nazi Germany in 1941, and ultimately reinvaded and reoccupied in 1944 by the Soviet Union.
The Battle of Paju was fought in Paju, near Valga, Estonia, on 31 January 1919 during the Estonian War of Independence. After heavy fighting, the Tartu-Valga group of the Estonian Army pushed the Red Latvian Riflemen out of the Paju Manor. It was the fiercest battle in the early period of war. Estonian commander Julius Kuperjanov fell in the fighting.
The 8th Army was a field army of the Soviet Red Army during the Second World War.
The background of the Winter War covers the period before the outbreak of the Winter War between Finland and the Soviet Union (1939–1940), which stretches from the Finnish Declaration of Independence in 1917 to the Soviet-Finnish negotiations in 1938–1939.
Foreign support in the Winter War consisted of materiel, men and moral support to the Finnish struggle against the Soviet Union in the Winter War. World opinion at large supported the Finnish cause. The Second World War had not yet begun in earnest and was known to the public as the Phoney War; at that time, the Winter War saw the only real fighting in Europe besides the German and Soviet invasion of Poland, and thus held major world interest. The Soviet aggression was generally deemed unjustified. Various foreign organizations sent material aid, such as medical supplies. Finnish immigrants in the United States and Canada returned home, and many volunteers traveled to Finland to join Finland's forces: 8,700 Swedes, 1,010 Danes, about 1,000 Estonians, 725 Norwegians, 372 Ingrians, 366 Hungarians, 346 Finnish expatriates, 4 Latvians, 2 Lithuanians and 190 volunteers of other nationalities made it to Finland before the war was over.
The Meredessantpataljon, was a short-lived Estonian marine infantry battalion during the Estonian War of Independence of the Estonian Defence Forces subject to the Estonian Navy. The battalion was created from the crews of the Estonian surface warships, students and Finnish volunteer soldiers. The battalion was created and later disbanded in Tallinn after it had fulfilled its military objectives in 1919.
The Orel–Kursk operation was an offensive conducted by the Southern Front of the Russian Soviet Federative Socialist Republic's Red Army against the White Armed Forces of South Russia's Volunteer Army in Orel, Kursk and Tula Governorates of the Russian Soviet Federative Socialist Republic between 11 October and 18 November 1919. It took place on the Southern Front of the Russian Civil War and was part of the wider October counteroffensive of the Southern Front, a Red Army operation that aimed to stop Armed Forces of South Russia commander Anton Denikin's Moscow offensive.
The Revolt of the Ingrian Finns was an uprising of Ingrian Finns in Ingria during the Russian Civil War and Heimosodat, the uprising began as small pockets of resistance in 1918, with organized resistance efforts beginning in January 1919 with the establishment of both the Temporary Caretaker Committee of Northern and Western Ingria, and lasting until the collapse of the Kirjasalo Republic on 5 December 1920.
Pohjan Pojat was a Finnish military brigade in 1918–1919, the second group of Finnish volunteers to enlist to take part in the Estonian War of Independence and sometimes the Latvian War of Independence, closely following behind the 1st Finnish Volunteer Corps regiment led by Colonel Martin Ekström.
Finnish volunteers 
Soviet Russia 
Martin Ekström 
Aleksander Paulus