Vilnius Region in the context of "Soviet–Lithuanian Peace Treaty"

The Molotov–Ribbentrop Pact, officially the Treaty of Non-Aggression between Germany and the Union of Soviet Socialist Republics, and also known as the Hitler–Stalin Pact, the Berlin–Moscow Pact and the Nazi–Soviet Pact, was a non-aggression pact between Nazi Germany and the Soviet Union, with a secret protocol establishing Soviet and German spheres of influence across Eastern Europe. The pact was signed in Moscow on 24 August 1939 (backdated 23 August 1939) by Soviet Foreign Minister Vyacheslav Molotov and German Foreign Minister Joachim von Ribbentrop.

Tripartite discussions between the Soviet Union, the United Kingdom and France had broken down after the Soviet Union was excluded from the Munich Agreement in September 1938. Joseph Stalin, the General Secretary of the Communist Party of the Soviet Union, had indicated that the USSR was willing to support Czechoslovakia militarily if France did so as well. Subsequently, rapprochement between Soviet Union and Nazi Germany began in early 1939. Later that year the Soviet-German pact was agreed, committing both sides to neither aid nor ally itself with an enemy of the other for the following 10 years. Under the Secret Additional Protocol of 23 August 1939, Germany and the Soviet Union agreed to partition Poland; Latvia, Estonia, Finland and Bessarabia were allotted to the Soviet sphere, while Lithuania – apart from the Vilnius region, whose "interests" were recognized – lay in the German sphere (Lithuania – including the Vilnius region, but excluding a strip of land – was only transferred to the Soviet sphere by the 28 September 1939 Boundary and Friendship Treaty). In the west, rumored existence of the Secret Protocol was proven only when it was made public during the Nuremberg trials.

54°30′N 25°45′E / 54.500°N 25.750°E / 54.500; 25.750The Republic of Central Lithuania (Polish: Republika Litwy Środkowej, Lithuanian: Vidurio Lietuvos Respublika), commonly known as the Central Lithuania, and the Middle Lithuania (Polish: Litwa Środkowa, Lithuanian: Vidurinė Lietuva, Belarusian: Сярэдняя Літва, romanized: Siaredniaja Litva), was an unrecognized short-lived puppet state of Poland, that existed from 1920 to 1922. It was founded on 12 October 1920, after the successful Żeligowski Mutiny, during which the volunteer 1st Lithuanian–Belarusian Division under the command of general Lucjan Żeligowski seized the Vilnius Region that Lithuania made claims to. It was incorporated into Poland on 18 April 1922.

Vilnius, the historical capital of Lithuania, had a majority Polish-speaking population with a Lithuanian-speaking minority of only 2–3%. Therefore, the Polish authorities decided that the region should belong to the newly-established Polish state, and attempted to implement this idea using military force, ignoring the Curzon Line and taking advantage of the fact that victorious Poles after the Battle of Warsaw were advancing to the East against the Bolsheviks in the Polish–Soviet War. The Poles reasoned that they were justified in seizing as many mixed areas as possible, as well as to protect the Catholic, predominantly Polish-speaking population in disputed areas. Being utterly militarily outmatched, Lithuania did not stand a chance to maintain control of the region. This led to the renewal of Polish–Lithuanian War, where the so-called Żeligowski Mutiny, secretly ordered by Józef Piłsudski, was part of the military operation, fully supported and backed on the flanks by the Polish army, and consequently to the establishment of the so-called Republic of Central Lithuania.

The Polish–Lithuanian War was an undeclared war fought in the aftermath of World War I between newly independent Lithuania and Poland, with fighting mainly in the Vilnius and Suwałki regions, which was part of the Lithuanian Wars of Independence and lasted from May 1919 to 29 November 1920. From the spring of 1920 onward, the conflict happened alongside the wider Polish–Soviet War and was affected by its progress. It was subject to unsuccessful international mediation at the Conference of Ambassadors and the League of Nations.

After World War I, the military and political situation in the region was chaotic, as multiple countries, notably Lithuania, Poland, and Soviet Russia, vied with each other over control of overlapping areas. The Polish–Lithuanian conflict was centered on Vilnius, which the Council of Lithuania declared the capital of the restored Lithuanian state. Control of Vilnius was transferred from Germans to Poles on January 2, 1919, but the Polish paramilitary lost the city to the Bolsheviks on January 5. The Polish Army seized Vilnius again on April 19, 1919 and came in contact with the Lithuanian Army fighting in the Lithuanian–Soviet War. Despite the antagonism over Vilnius, the Lithuanian and Polish armies sometimes cooperated when fighting against a common enemy, the Bolsheviks. As Lithuanian–Polish relations worsened, the Entente drew two demarcation lines in hopes to stall further hostilities. The lines did not please either side and were ignored. The first clashes between Polish and Lithuanian soldiers occurred on April 26 and May 8, 1919, near Vievis. With the Polish coup against the Lithuanian government failing in August 1919, the front stabilized until the summer of 1920.

The Kresy myth (Polish: mit Kresów) ('myth' in Polish sometimes not referring to a necessarily false belief as in English) also known as the Kresy Cult (kult Kresów) and the Kresy Legend (legenda Kresów) is the name to a certain sense of views or attitudes in connection to nostalgic attachment of the former eastern borderlands of Poland (Kresy), sometimes in an ethnic nationalist sense, sometimes as a multicultural land dominated by Polish culture. According to Andrii Portnov, the Kresy is seen even as "'the lost paradise' of Poland’s 'civilisational mission'" at the same time as the location of "bloody and romantic clashes with the Cossacks and Tatars". The Kresy was part of the Polish–Lithuanian Commonwealth and the Second Polish Republic but since the latter's fall is no longer Poland but instead present-day Ukraine, Belarus, Lithuania. The Kresy, in certain definitions, extend beyond the areas which became part of interwar Poland. In particular after the territorial changes, population transfers of World War II, the nostalgia focused on the Vilnius region and Eastern Galicia, notably Lviv (Lwów in Polish). It is argued exponents of the discourse tend to focus specifically on Poles, living in the Kresy without paying sufficient attention to the region's Ukrainian, Lithuanian, Rusyn, or Belarusian inhabitants.