In 1809, in accordance with Treaty of Fredrikshamn Sweden surrendered Finland to Russia, and the Diet of Porvoo pledged loyalty to Russian Emperor Alexander I.

Population migration from actual parts of the Russia Empire to Finland was de facto prohibited until early 1900's.

With the Russian Empire's collapse during World War I, Finland took the opportunity to declare its full independence, which was shortly recognized by the USSR "in line with the principle of national self-determination that was held by Lenin.

Voluntary activists arranged expeditions to Karelia (heimosodat), which ended when Finland and the Russian Soviet Federative Socialist Republic signed the Treaty of Tartu in 1920.

Of all the continental European nations combating, as part of World War II, Helsinki and Moscow were the only capitals not occupied.

However, after the failed 1991 August Coup in Russia, Finland recognized the Baltic states and restored diplomatic relations with them.

Finland accused Russia of deliberately using refugees as weapons as part of its hybrid warfare following worsening relations between the two countries.

The spying was uncovered in spring 2013, and as of October 2013[update] the Finnish Security Intelligence Service (Supo) was investigating the breach.

Additionally, he believes that transatlantic cooperation is needed for the maintenance of sovereignty and security of some EU member states, including Finland.

[20] In the wake of the 24 February 2022 Russian invasion of Ukraine, support among the Finnish populace for NATO membership increased from below 30% to 60-70%.

[28] Finland formally became a member of NATO on 4 April 2023 during a scheduled summit,[29] finalizing the fastest accession process in the treaty's history.