The Greater Poland uprising began 101 years ago in Poznań. By half of January, most of the region was freed from the occupants. The territories regained by the insurgents were confirmed as part of the Republic of Poland by the truce in Trewir signed by Germany and the Entente on February 16th 1919. According to the treaty, the Greater Poland front was acknowledged as an Allied front. The final victory was sealed by the signing of the Versailles Treaty on June 28th 1919, which guaranteed Poland the return of almost entire Greater Poland region.
Source: Poland Daily