New nation-states of central and eastern Europe

Poland regained independence in November 1918 after more than a century of partition among Russia, Prussia, and Austria, with Józef Piłsudski as head of state. The Treaty of Versailles gave Poland Baltic access through the Polish Corridor, and a 1921 plebiscite in Upper Silesia produced a division that granted Poland the industrially richer portion despite an overall vote favoring Germany. Poland's eastern border was settled through the Polish-Soviet War (1919–1921), in which Polish forces halted the Red Army's advance at the "Miracle on the Vistula" near Warsaw in August 1920, with the resulting Treaty of Riga (1921) granting Poland a border considerably more favorable than the Western-proposed Curzon Line. Poland became a heterogeneous state, with Ukrainian, Belarusian, Jewish, and German minorities making up roughly a third of its population.