Causes of the Polish – Soviet War The prehistory . The territory , where this conflict broke out , was a part of the medieval Kievan Rus , and after the disintegration of this united Ruthenia n state ( in the middle of 12th century ) belonged to the Ruthenian princedoms of Halych - Volhynia , Polotsk , Lutsk , Terebovlia , Turov - Pinsk etc . The majority of these principalities have been ruined during the Tatar - Mongol invasion in the middle of 13th century . Some territories in the Dniepr region and Black Sea Coast for long years lost Ruthenian settled population and became the so - called " Wild Steppe " ( i . e . , territory of the Pereyaslavl ) . After the Tatar - Mongol invasion these territories become an object of expansion of the Polish kingdom and the Lithuanian princedom . For example , in the first half of 14th century Kiev , the Dniepr region , also the region between the rivers Pripyat and West Dvina were captured by Lithuania , and in 1352 the Halych - Volhynia princedom was divided by Poland and Lithuania . In 1569 , according to the Lublin Union , the majority of the Ruthenian territories possessed by Lithuania , passed to the Polish crown . The serfdom and Catholicism extended in these territories . The local aristocracy was incorporated into the Polish aristocracy . Cultural , language and religious break between the supreme and lowest layers of a society arose . The combination of social , language , religious and cultural oppressions had led to destructive popular uprisings of the middle of 17th century , which the Polish - Lithuanian state could not recover from . In many territories incorporated into the Russian empire in 1772 - 1795 after the partitions , the domination of the Polish aristocracy was kept , in the territories incorporated into the Austro - Hungarian empire , the domination of the Polish aristocracy has been added with active planting of German language and culture . During the First World War Austro - Hungarian authorities undertook reprisals against Russia - oriented people of the Eastern Galicia and the Polish left - nationalist movement led by Piłsudski got the support of the Central Powers for struggle against Russia . In the consequence of the revolution in Russia and the fall of Hohenzollern and Habsburg empires in the end of World War I Poland regained independence . The Polish leaders decided to retrieve as many of the territories that were parts of the Polish - Lithuanian state in 1772 as possible . The situation . In the aftermath of World War I , the map of Central and Eastern Europe had drastically changed . The Treaty of Brest - Litovsk ( March 3 , 1918 ) , by which Russia had lost to Imperial Germany all the European lands that Russia had seized in the previous two centuries , was rejected by the Bolshevik government in November 1918 , following armistice , the surrender of Germany and her allies , and the end of World War I . Germany , however , had not been keen to see Russia grow strong again and — exploiting her control of those territories , had quickly granted limited independence as buffer state s to Finland , Estonia , Latvia , Lithuania , Poland , Belarus and Ukraine . As Germany ' s defeat rendered her plans for the creation of those Mitteleuropa puppet state s obsolete , and as Russia sank into the depths of the Russian Civil War , the newly emergent countries saw a chance for real independence and were not prepared to easily relinquish this rare gift of fate . At the same time , Russia saw these territories as rebellious Russian provinces but was unable to react swiftly , as it was weakened and in the process of transforming herself into the Soviet Union through the Russian Revolution and Russian Civil War that had begun in 1917 . With the success of the Greater Poland Uprising in 1918 , Poland had re - established its statehood for the first time since the 1795 partition and seen the end of a 123 years of rule by three imperial neighbors : Russia , Germany , and Austria - Hungary . The country , reborn as a Second Polish Republic , proceeded to carve out its borders from the territories of its former partitioners . The Western Powers , in delineating the new European borders after the Treaty of Versailles , had done so in a way unfavorable to Poland . Her western borders cut her off from the coal - basin and industrial regions of Silesia , leading to the Silesian Uprisings of 1919 - 1921 . The eastern Curzon line left millions of Poles , living east of the Bug River , stranded inside Russia ' s borders . Poland was not alone in its newfound opportunities and troubles . Most if not all of the newly independent neighbours began fighting over borders : Romania fought with Hungary over Transylvania , Yugoslavia with Italy over Rijeka , Poland with Czechoslovakia over Cieszyn Silesia , with Germany over Poznań and with Ukrainians over Eastern Galicia ( Galician War ) . Ukrainians , Belarusians , Lithuanians , Estonians and Latvians fought against themselves and against the Russians , who were just as divided . Spreading communist influences resulted in communist revolutions in Munich , Berlin , Budapest and Prešov . Winston Churchill commented : " The war of giants has ended , the wars of the pygmies begin . " All of those engagements – with the sole exception of the Polish - Soviet war – would be short - lived border conflicts . The Polish - Soviet war likely happened more by accident than design , as it is unlikely that anyone in Soviet Russia or in the new Second Republic of Poland would have deliberately planned a major foreign war . Poland , its territory a major frontline of the First World War , was unstable politically ; it had just won the difficult conflict with the West Ukrainian National Republic and was already engaged in new conflicts with Germany ( the Silesian Uprisings ) and with Czechoslovakia . Polish government was just beginning to organise and had little if any control over various border areas . Six currencies affected by various ( and rising rapidly ) inflation rates were in circulation . Economy was in shambles , some areas were experiencing food shortages , crime was high and a threat of an armed coup d ' etat by some factions was serious . The situation in Russia was similar . The attention of revolutionary Russia , meanwhile , was predominantly directed at thwarting counter - revolution and intervention by the western powers . Bolshevik Russia had barely survived its second winter of blockade and resulting mass starvation and was in the middle of a bloody civil war . Lenin controlled only a part of central Russia , and the Bolsheviks were surrounded by powerful enemies who needed to be defeated before any thought could be given to advance beyond the unclear Soviet borders . No matter their intent , Lenin and other communist leaders were simply incapable of moving beyond those borders . While the first clashes between Polish and Soviet forces occurred in February 1919 , it would be almost a year before both sides realised that they were engaged in a full war . Piłsudski ' s motives . Polish politics was under the strong influence of the statesman Józef Piłsudski , who envisioned a federation ( the " Federation of Międzymorze " ) , a Polish - led federation comprising Poland , Lithuania , Ukraine and other Central and East Europe an countries now emerging out of the crumbling empires after the First World War . The new union would have had borders similar to those of the Polish - Lithuanian Commonwealth in the 15th – 18th centuries ; and it was to be a counterweight to , and restraint upon , any imperialist intentions of Russia or Germany . To this end , Polish forces set out to secure vast territories in the east . However Piłsudski ' s federation plan was opposed by another influential Polish politician , Roman Dmowski , who favoured creating a larger , national Polish state . It is also imperative to understand that Poland had never any intention of joining the Western intervention in the Russian Civil War or conquering Russia , as it has done once in the 17th century during the Dimitriads . On the contrary , after the White Russians refused to recognise Polish independence , Polish forces acting on orders from Piłsudski delayed or stopped their offensives several times , reliving pressure from Bolshevik forces and thus substantially contributing to White Russian defeat . Lenin ' s motives . The Red Army ' s advance was not intent to conquer the entire world , or even Europe . 36 Soviet division s were not prepared to succeed where Tsarist failed earlier with 150 . This even Lenin realized . Conflict with Poland , hardly a world power , was both winnable and could be the spark to engulf the world in a revolutionary flame . In April 1920 , when the Red Army ' s major push towards Polish hinterlands took place , the soldiers and commanders were told that defeat of Poland was not only necessary but simply sufficient for the " oppressed masses of the proletariat " to rise worldwide and create a " workers ' paradise . " In the words of General Tukhachevski : " To the West ! Over the corpse of White Poland lies the road to world - wide conflagration . March on Vilno , Minsk , Warsaw ! " . In late 1919 the leader of Russia ' s new communist government , Vladimir Lenin , was inspired by the Red Army ' s civil - war victories over White Russian anti - communist forces and their western allies , and began to see the future of the revolution with greater optimism . The Bolsheviks doctrine said that historical processes would lead to proletariat victory worldwide , and that the nation state s would be replaced by a worldwide communist community . War with Poland was needed if the communist revolution in Russia was to be linked with the expected revolutions in the West , such as the one in Germany . Early Bolshevik ideology made it clear that Poland , which was located in between Russia and Germany , had to become the bridge that the Red Army would have to cross to fulfill the Marxist doctrine . It was not , however , until the Soviet successes in mid - 1920 that this idea became for a short time dominant in Bolshevik policies . Germany in 1918 - 1920 was a nation torn by social discontent and embroiled in political chaos . Since the Kaiser ' s abdication at the end of the First World War , it had seen a series of major internal disturbances , including government takeovers , several general strikes , some leading to communist revolutions ( e . g . the Bavarian Soviet Republic ) , By July 1920 , which is when the Soviets were on the verge of taking Warsaw , the Weimar Constitution was still brand new and the humiliating Peace of Versailles , even more so . Germany unstable government had to deal with separatist tendencies , an ongoing conflict , not far from a civil war between the Spartacist League ' s and Communist Party of Germany and the right - wing Freikorps , all under the watchful and humiliating eyes of the Allied powers . Red Army ' s remaking of the Versailles system was seen as a major force that could shake the existing system imposed by the victorious western Entente . As Lenin himself remarked , " That was the time when everyone in Germany , including the blackest reactionaries and monarchists , declared that the Bolsheviks would be their salvation . " In April 1920 Lenin would complete writing " The Infantile Disease of " Leftism " in Communism " , a guide to the final stages of the Revolution . He became overconfident , entertaining the thoughts of a serious war with Poland . According to him and his adherents , the Revolution in Russia was doomed unless it was to become worldwide . The debate in Russia was " not as to whether the Polish bridge should be crossed , but how and when . " According to Lenin ' s doctrine of " revolution from outside " Red Army ' s advance into Poland would be an opportunity " to probe Europe with the bayonet s of the Red Army " , the first attempt to export the Bolshevik Revolution by any means necessary . In a telegram , Lenin wrote : " We must direct all our attention to preparing and strengthening the Western Front . A new slogan must be announced : Prepare for war against Poland . " References . See Polish - Soviet War # Notes