The Russian revolution of 1905 led to social and political unrest and a breakdown of security in Finland, which was then a Grand Duchy under the sovereignty of the Russian Czar. Citizen militias were formed as a response, but soon these would be transformed along political (left-right) lines. The Russian Revolution of 1917 and the subsequent independence of Finland also caused conflicts in the country. On January 27, 1918, the Finnish government ordered the disarmament of all remaining Russian garrisons with the forces of the White Guard, and on the same day the Reds proclaimed revolution, leading to a bloody civil war. White Guards, led by Gen. C.G.E. Mannerheim, constituted the bulk of the victorious White Army during the Finnish Civil War (1918).
After the war the Finnish Defence Forces and a regular police service were founded. From 1919–1934 White Guards were considered a voluntary part of the army, and separate Guard formations were in the reserve, but in 1934 all defence was consolidated into the regular army and the Guard became a voluntary defence training organization only. Politically it was neutral, although unofficially it was anti-leftist, clearly anti-Communist and conservative and largely rejected by the labor movement and the political left. However, units of it formed the main forces of the Lapua Movement's abortive coup d'état, the Mäntsälä Rebellion in 1932. White Guardsmen served in the regular army during the Second World War. The White Guard was disbanded according to the terms of the Finno-Soviet peace treaty after the Second World War.
Similar militias existed in Estonia, Latvia and Lithuania, lands that, like Finland, were under Russian sovereignty until the end of World War I. These militias remained in existence until World War II, evolving somewhat into home guard militias. The phenomenon should be distinguished from the Freikorps established in Germany after its defeat in World War I, although some similarities exist.
During the first years of the 20th century, Russia had been working on the abolition of Finland's autonomous status. As a result, there was strong discontent in Finnish society. In 1905 Russia lost the Russo-Japanese War. This stunning and unexpected defeat led to the Russian Revolution of 1905. In Finland the unrest was expressed in the Finnish general strike of 1905. During the strike Finnish police forces were effectively disbanded, as they had been closely associated with the occupying Russian authorities. Municipal, mostly unarmed, security guards were spontaneously organised by individuals associated with the constitutional and Social Democratic parties. At first all political groups were able to work together, but towards 1906 the civil guards of large towns had become divided along party lines. The first violent clash between Red and White Guards occurred in July 1906 in Helsinki, but after the return of Finnish autonomy the moderate Social Democrats and the whole constitutional party withdrew from military activities. However, the radicalized Red Guard of Helsinki did not disband, despite an order from the Social Democratic leadership to do so, and took part in the mutiny at Viapori fortress alongside revolutionary, anti-imperial Russian soldiers. In the ensuing fighting Czarist Russian troops destroyed the Red Guard as an organisation.
The February Revolution in Russia in 1917 caused the collapse of Russian political and military power in Finland. Again, the Russian-associated Finnish police were effectively disbanded, while the largely undisciplined Russian troops engaged in violence, mostly towards their own officers. During the summer of 1917 paramilitary groups were formed for protection and to preserve order. Although the founding of these "fire brigades" was often done in a non-partisan manner, they often split into two opposing factions during the autumn of 1917. The initially unarmed Red and White Guards strove to obtain weapons. The Red Guards usually were able to get arms from revolutionary Russian military units, while the White Guards got theirs from Swedish and German supporters abroad. At the same time, political tensions between socialists and non-socialists escalated. Inside the Social Democratic party, the official leadership was derailed while the executive committee of the Red Guards and the labour unions gained more power.