Upper Silesia plebiscite

The Upper Silesia plebiscite was a plebiscite mandated by the Versailles Treaty and carried out on 20 March 1921 to determine a section of the border between Weimar Germany and Poland. The region was ethnically mixed with both Germans and Poles; according to prewar statistics, ethnic Poles formed 60 percent of the population. Under the previous rule by the German Empire, the Poles had faced discrimination and racism, making them effectively second class citizens. The period of the plebiscite campaign and interallied occupation was marked by violence. There were two Polish uprisings, and German volunteer paramilitary units came to the region as well.

The area was policed by French, British, and Italian troops, and overseen by an Interallied Commission. The Allies planned on a partition the region, but a Polish uprising took control of over half the area. The Germans responded with volunteer paramilitary units from all over Germany, which fought the Polish units. In the end, after renewed Allied military intervention, the final position of the opposing forces became, roughly, the new border. The decision was handed over to the League of Nations, which confirmed this border, and Poland received roughly one third of the plebiscite zone by area, including the greater part of the industrial region.

The earliest exact census figures on ethnolinguistic or national structure (Nationalverschiedenheit) of the Prussian part of Upper Silesia, come from year 1819. The last pre-World War I general census figures available, are from 1910 (if not including the 1911 census of school children - Sprachzählung unter den Schulkindern - which revealed a higher percent of Polish-speakers among school children than the 1910 census among the general populace). Figures (Table 1.) show that large demographic changes took place between 1819 and 1910, with the region's total population quadrupling, the percent of German-speakers increasing significantly, and that of Polish-speakers declining considerably. Also the total land area in which Polish language was spoken, as well as the land area in which it was spoken by the majority, declined between 1790 and 1890.

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