On 22 April 1920, the Republic of Poland and the People’s Republic of Ukraine signed an agreement in Warsaw that came to be known as the “Piłsudski–Petlyura alliance”. It established a link between two states that were fighting to keep their independence in the face of the common enemy, Soviet Russia, that attacked them. The direct objective of the treaty was to put up a joint military effort against the Bolshevik Russia that tried to export the revolution. At the same time, the agreement also served to realize Piłsudski’s ambitious plans.

Keywords: Polish-Bolshevick war, 1920, Polish-Ukrainan relations