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.