Throughout its history, Finland’s relations with Russia have generally been determined by Russian attempts to secure control over the eastern part of the Baltic Sea region. In medieval times, it was mainly about the control of trade routes, especially between Novgorod, and Western Europe and Byzantium. After the founding of the new city of St. Petersburg by Peter the Great in 1703, the rulers of Russia were faced with the problem of ensuring security to that city. From a Russian point of view, it became vitally important to gain control over lands on the eastern side of the Baltic Sea. When Finland became a Russian province in 1809, it seemed that the Baltic security dilemmas of Russia had fi nally been resolved. However, the collapse of Tsarist Russia in 1917 changed that particular situation. Finland became independent, and Russia’s border moved east to the outskirts of St. Petersburg (renamed Petrograd during World War I). For the leaders of the Soviet Union, which had replaced the Romanov Empire, World War II provided an opportunity to try to regain lost Finnish territories. Although the Red Army did not manage to conquer Finland, during two wars (occurring between 1939–1940 and 1941–1944), the post war settlement saw the Soviet-Finnish border shift back westwards. Finland also had to reckon with the requirements of the USSR’s security policy and make it a priority of its own foreign policyAfter the collapse of the Soviet Union in 1991, Finland modified its policy of neutrality and adopted a doctrine of non-alignment that has remained in place to this day. However, the increase of tensions in international relations in recent years, due to Russia’s aggressive foreign policy threatening its neighbours, has forced Finnish statesmen to rethink their country’s security policy. After the Russian invasion of Ukraine in 2022, Finland, together with Sweden, decided to apply for NATO membership. The ratification procedure is ongoing. The aim of this paper is to analyse, in a longer historical perspective, what Finland’s place was as regards the Russian and Soviet security policy, from Peter the Great to our times. The methodological approach refl ects the chronology of events which have occurred in the eastern part of the Baltic Sea region in the last 300 years. They are described to provide readers with necessary facts, and create the background for conclusions on the reasons for the Russian/Soviet policy towards Finland and, in a broader sense, the northern coasts of the Gulf of Finland.