Aftermath of World War I: The Parliament of Poland establishes Silesian Voivodeship before the Polish-German plebiscite.

The aftermath of World War I saw far-reaching and wide-ranging cultural, economic, and social change across Europe, Asia, Africa, and in areas outside those that were directly involved. Four empires collapsed due to the war, old countries were abolished, new ones were formed, boundaries were redrawn, international organizations were established, and many new and old ideologies took a firm hold in people's minds. Additionally, culture in the nations involved was greatly changed. World War I also had the effect of bringing political transformation to most of the principal parties involved in the conflict, transforming them into electoral democracies by bringing near-universal suffrage for the first time in history, as in Germany, United Kingdom of Great Britain and Ireland, and the United States.

The parliament of Poland is the bicameral legislature of Poland. It is composed of an upper house and a lower house. Both houses are accommodated in the Sejm and Senate Complex in Warsaw. The Constitution of Poland does not refer to the Parliament as a body, but only to the Sejm and Senate.

The Silesian Voivodeship was an autonomous province (voivodeship) of the Second Polish Republic. The bulk of its territory had formerly belonged to the German/Prussian Province of Silesia and became part of the newly reborn Poland as a result of the 1921 Upper Silesia plebiscite, the Geneva Conventions, three Upper Silesian Uprisings, and the eventual partition of Upper Silesia between Poland, Germany and Czechoslovakia. The remainder had been the easternmost portion of Austrian Silesia which was partitioned between Poland and Czechoslovakia following the collapse of Austria-Hungary, the Polish–Czechoslovak War and the Spa Conference of 1920. The capital of the voivodeship was Katowice.