Lake Ladoga Stolbovo, the northern and western coast was ceded by Russia to Sweden. In 1721, after the Great Northern War, it was restitution to Russia by the Treaty of Nystad. Later, in 1812–1940 the lake was shared between Finland and Russia. According to the conditions of the 1920 Tartu Peace Treaty militarization of the lake was severely restricted. However, both Soviet Russia and Finland had flotillas in Ladoga (see also Finnish Ladoga Naval Detachment). After the Winter War (1939–40) according to the Moscow Peace Treaty, Ladoga, previously shared with Finland, became an internal basin of the Soviet Union. During the Continuation
Finnish Ladoga Naval Detachment Finnish Ladoga Naval Detachment Finnish Ladoga Naval Detachment () was a Finnish naval unit stationed on Lake Ladoga between 1920-1940 and 1941-1944. The Treaty of Tartu was signed by the Russians and the Finns in 1920. It included terms which limited the size of naval vessels on Ladoga to 100 tons, and the calibre of their armament to a maximum of 47 mm. When the Finns embarked on their naval rebuilding program in the early 1930s, some vessels were purposely designed to fit this 100 t limitation, including a small submarine. The Finns, however, found more use for their few