There was not a country called Estonia, with recognized borders, until 1917. I’m copying this from Wikipedia:
“Territorial changes of the Baltic states refers to the redrawing of borders of Lithuania, Latvia and Estonia after 1940. The three republics, formerly autonomous regions within the former Russian Empire and before that of former Polish–Lithuanian Commonwealth, gained independence in the aftermath of World War I and the Russian Revolution of 1917.
“After a two-front independence war fought against both Bolshevist Russian and Baltic German nationalist forces, the countries concluded peace and border treaties with Soviet Russia in 1920. However, with World War II and the occupation and annexation of these republics into the Soviet Union twenty years after their independence, certain territorial changes were made in favor of the Russian SFSR.
“This has been the source of political tensions after they regained their independence with the dissolution of the Soviet Union in 1988. Some of the disputes remain unresolved.”