The demilitarisation of the Aland Islands dates back to the 1856 Treaty of Paris bringing the end to the Crimean War. France, Great Britain and Russia signed the Convention of Demilitarisation of the Islands annexed to the peace treaty. Demilitarisation was broadened to include neutralisation in the 1921 Convention on the Demilitarisation of the Aland Islands. The demilitarised status of Aland was confirmed in the Moscow Treaty between Finland and the Soviet Union from 1940, and in the 1947 Paris Peace Treaty.
Finland is supposed to defend the demilitarization and neutralization of the Åland Islands in the event of armed attack. The local population is exempt from the obligation of military service, but it does not apply to those who came to Aland after reaching the age of 12.