Silesian Uprisings

The Silesian Uprisings (Polish: Powstania śląskie) was a series of three military insurections (1919-1921) of the Polish people in the Upper Silesia region against the German/Prussian forces in order to force them out the region and join it with Poland, that regained her independence after the World War I (1914-1918)
Korfanty in 1920

The Treaty of Versailles had ordered a plebiscite in Upper Silesia to determine whether the territory should be part of Germany or Poland. In the background, strongarm tactics and discrimination of Poles led to rioting and eventually to the first two Silesian Uprisings (1919 and 1920). In the plebiscite, around 59,6% (~500,000) votes were cast for remaining in Germany and this result led to the Third Silesian Uprising in 1921. League of Nations was asked to settle the matter. In 1922 a six-week investigation found that the land should be split. The decision was accepted by both countries, and the majority of Upper Silesians. Approximately 736,000 Poles and 260,000 Germans lived in Polish Silesia and 532,000 Poles and 637,000 Germans in German Silesia.

The Silesian Uprisings (1919-1921)

First Silesian Uprising: 16 August-26 August 1919

Second Silesian Uprising: 19 August-25 August 1920

Third Silesian Uprising: 2 May-5 July 1921

References:

H.Zieliński, Rola powstania wielkopolskiego oraz powstań śląskich w walce o zjednoczenie ziem zachodnich z Polską (1918-1921), [w:] Droga przez Półwiecze''.