With Denikin's defeat and the Ukrainians in severe trouble, they made an alliance with the Poles in April 1920, the combined Polish-Ukrainian forces pushed back the Reds, who occupied most of Ukraine. This was part of the Polish–Soviet War, and ended up with gains for Poland after the treaty of Riga in 1921, but with nothing for the Ukrainians who were fully defeated. The Ukrainians based in Poland tried to launch offensives and raids into Soviet Ukraine, but these failed considerably.