Zdroj wikipedia: The Polish–Soviet war erupted in 1919 in the aftermath of World War I. The root causes were twofold: a territorial dispute dating back to Polish–Russian wars in the 17–18th centuries; and a clash of ideology due to USSR's goal of spreading communist rule further west, to Europe (Soviet westward offensive of 1918–19). At that time both countries had just undergone transition: in 1918 Poland reclaimed independence after 123 years of partitions. In 1917 the October Revolution replaced the liberal, democratic Provisional Government, that had previously displaced the Tsar in Russia, with Soviet rule. The war ended with the Treaty of Riga in 1920, which settled the border issue and regulated Polish-Soviet relations until the German-Soviet invasion of Poland in 1939.


