Warschauer Vertrag
The Treaty of Warsaw (also the Polish-Ukrainian or Petliura-Piłsudski Alliance or Agreement) of April 1920 was a military-economical alliance between the Second Polish Republic, represented by Józef Piłsudski, and the Ukrainian People's Republic, represented by Symon Petliura, against Bolshevik Russia. The treaty was signed on 21 April 1920, with a military addendum on 24 April.