For Polish Communists, who were sidelined only out of temporary necessity after the signing of the Sikorski-Majski pact, the formation of an army which would fight – unconditionally – alongside the Red Army was of the highest priority. In February 1943 Stalin met with Colonel Zygmunt Berling, who willingly remained in the Soviet Union after the evacuation of Anders’ Army, to explore the possibility of organizing a Polish division. An organization was needed, however, to front such an undertaking. Thus in March 1943 the Organization of Polish Patriots was founded, composed mainly out of Communists, which then approached Stalin with a request to form a Polish unit in Sielce near the Oka River. Polish deportees, mainly from the years 1939-1941, flooded the units staging area, many of whom simply did not make it in time for Anders’ Army. Although most of the unit’s officers came from the Red Army, care was taken to incorporate Polish symbols: uniforms were made in the Polish pre-war fashion, the day began with Holy Mass, and the 1st Division, named after Tadeusz Kosciuszko (who led a Polish insurrection against Russia and Prussia at the end of the 17th Century) took its oath on July 15, 1943, on the anniversary of the Polish victory over the German Teutonic Nights at the Battle of Grunwald in 1410. On October 12-13 1943 the division took part in bloody fighting by Lenino, in Belarus. The anniversary of this battle was celebrated as the official holiday of the Polish Army for half a century after the war.
By the Spring of 1944 the division had grown into the First Polish Army, and in the summer of 1944 the formation of a Second Polish Army had begun. These soldiers fought at the Battle of the Vistula (July-August 1944), and in September took the eastern bank of Warsaw, while also helping the embattled Home Army in Warsaw. In the first months of 1945, the First Army played an important role in breaking the Pomeranian Wall, capturing Kolobrzeg, Gdansk, Gdynia and finally Berlin. The Second Army fought by Nysa Luzycka, Budziszyn and Czestochowa (finally reaching the outskirts of Prague).
From 1943 to 1945 18,000 soldiers of the Polish “People’s” Army died, and 50,000 were wounded. It was recognized that the Polish “People’s” Army was the largest allied force fighting alongside the Red Army. Representatives of the Polish “People’s” Army marched in the Moscow Victory Parade on June 24, 1945.