</ref> After the act of union between the West Ukrainian Republic and the Ukrainian People's Republic (UPR), Ternopol formally passed under the UPR's control. On 15 July 1919, the city was captured by Polish forces. In 1920 the exiled Ukrainian government of Symon Petlura accepted Polish control of Tarnopol and of the entire area after receiving the assurance of Józef Piłsudski, the Lithuanian born Field Marshal of the Polish Army, that there would be no peace with the Russians without creating a Ukrainian state. In July and August 1920 the Red Army captured Tarnopol in the course of the Polish-Soviet War. The city then served as the capital of the Galician Soviet Socialist Republic. Although the Poles and their Ukrainian allies badly defeated the Russians on the battle field and the Russians had offered to cede Ukraine and Belarus, Polish politicians in Warsaw refused to honor Piłsudski's promise. By the terms of the Riga treaty, the Soviets and Poles effectively partitioned Ukraine. For the next 19 years, the ethnically mixed Ternopol area remained in Polish control.