Greater Poland Uprising ( 1918 – 19 ) The Greater Poland Uprising of 1918 – 1919 , or Wielkopolska Uprising of 1918 – 1919 ( Polish : " powstanie wielkopolskie 1918 – 19 roku " ; ) or Posnanian War was a military insurrection of Poles in the Greater Poland region ( also called by the Germans the Grand Duchy of Poznań or Provinz Posen region ) against Germany . The uprising had a significant effect on the Treaty of Versailles , which granted a reconstituted Poland the area won by the Polish insurgents plus some additional territory , at the cost of German territory , all of which had previously been Polish territory , before the three Partitions of Poland carried out ( between 1787 and 1795 ) by the three powerful , neighbouring Empires of Austria , Prussia and Russia . Background . After the 1795 Third Partition of Poland ( Polish - Lithuanian Commonwealth ) , Poland had ceased to exist as an independent state . From 1795 through the beginning of the Great or First World War , several unsuccessful uprisings to regain an independent state took place . An 1806 uprising was followed by the creation of the Duchy of Warsaw which lasted for eight years before being partitioned again between Prussia and Russia . At the end of World War I , US President Woodrow Wilson ' s Fourteen Points met with opposition from European nations standing to lose power or territory . German politicians had signed an armistice leading to a cease fire on 11 November 1918 , with the Western and former Eastern front lines outside of Germany . Germany had signed the Treaty of Brest - Litovsk with Bolshevik Russia to settle the eastern frontiers . This Treaty did not take into account the millions of Poles living in what had been their territory which was in the middle . Therefore , from the date that the armistice was signed until the Treaty of Versailles was fully ratified in January 1920 , many territorial and sovereignty issues remained unresolved . Wilson ' s proposal for an independent Poland did not definitively set borders for Poland that could be universally accepted . Most of the part of Poland partitioned and annexed to Prussia in the late 18th century was still part of Germany at the close of World War I , with the rest of the subsequent post - World War I Polish territory being part of Russia and of Austria - Hungary . The portion which was part of Germany included the Provinz Posen , or territory of Greater Poland , of which Poznań ( Posen ) was a major industrial city . The majority of the population was Polish ( more than 60 % ) and was uncertain whether they would be repatriated within the proposed new Polish nation . The uprising . In late 1918 Poles with hopes for a sovereign Poland began serious preparations for an uprising after the Kaiser Wilhelm ' s abdication on 9 November 1918 , which marked the end of the German monarchy , which would be replaced by the Weimar Republic . The uprising broke out on 27 December 1918 in Poznań , after a patriotic speech by Ignacy Paderewski , Polish Prime Minister at that time , and a famous Polish pianist . The uprising forces consisted of members of the Polish Military Organization of the Prussian Partition , who started to form the " Straż Obywatelska " ( Citizen ' s Guard ) , later renamed as " Straż Ludowa " ( People ' s Guard ) and many volunteers — mainly veterans of World War I . The first contingent to reached the Bazar Hotel where the uprising broke out was 100 - men military campaign from " wildecka kompania Straży Ludowej " ( Wilda ’ s People ’ s Guard ) led by Antoni Wysocki . The ruling body was the " Naczelna Rada Ludowa " ( High Peoples ' Council ) — at the beginning members of the Council were against the uprising , but supported it a few days later : unofficially 3 January 1919 ; officially 8 and 9 January 1919 — and the military commanders : Captain Stanisław Taczak ( promoted to major , temporary commander 28 December 1918 – 8 January 1919 ) and later General Józef Dowbor - Muśnicki . The timing of the uprising was fortuitous for the insurgents , as between October 1918 and the first months of 1919 , internal conflict had weakened Germany , with soldiers and sailors engaged in mutinous actions against the monarchy and the officer corps . Demoralized by the signing of an armistice on 11 November 1918 , the new German government was further embroiled in subduing the German Revolution . By 15 January 1919 , the rebellious Polish forces managed to take control of most of the Province of Posen , and engaged in heavy fighting with the regular German army and the forces of the Grenzschutz , up until the renewal of the truce between the Entente and Germany on 16 February , which affected the Wielkopolska or Posen Province part of the front line . Skirmishes continued , however , until the signing of the Treaty of Versailles on 28 June 1919 . The Greater Poland Uprising is one of the two most successful Polish uprisings : the other was the Great Poland Uprising of 1806 which was ended by the entry of Napoleon ' s army . Many of the Wielkopolska insurgents also took part in the 1919 - 1921 uprisings in Silesia . Reaction . The uprising had a significant effect on the Versailles decisions , which granted Poland not only the area won by the insurgents , but a portion of the Province of Pomerania , as well as a few cities which lay beyond the demarcation line : Bydgoszcz , Leszno ( then respectively Bromberg and Lissa ) , as well as Rawicz ( the Polish Corridor ) . Some of them were predominantly German , others predominantly Polish . The riots also influenced the decision to have popular votes in Silesia , where the public was allowed to vote whether it wanted to be part of the German or Polish state . Germany ' s territorial losses following the Treaty of Versailles incited German revanchism and created problems such that the status of the independent Free City of Danzig and the Polish Corridor between East Prussia and the rest of Germany became an issue in German politics , Attending to the issues was part of Adolf Hitler ' s political platform , obviously with a strong bias towards Germany . Throughout the 1920s and 1930s , Poland refused several German proposals for popular referendum s , population transfers , highway projects and customs union reform .