The PKWN was formed in negotiations involving primarily the main Polish communist organizations, the Union of Polish Patriots (ZPP) and the Polish Workers' Party (PPR). The Polish communist movement had been decimated during the Soviet purges in the 1930s, but revived under Stalin's auspices beginning in 1940. The PPR was a new party organized in occupied Poland, the ZPP originated during the war in the Soviet Union. The PPR had already established in Warsaw a conspiratorial State National Council (KRN), which they declared to be the wartime national parliament. Because of war-related obstacles, the communist leaders arriving from Warsaw (the PPR delegation that included Władysław Gomułka and Bolesław Bierut) reached Lublin only on 31 July, and attained full agreement with the group from Moscow (ZPP) on 15 August. The documents they produced were antedated to 21 July to comply with the declarations issued as of 22 July.