Polish Armed Forces in the East in the context of "Polish People's Army"

The Eastern Front, also known as the Great Patriotic War in the Soviet Union and its successor states, and the German–Soviet War in modern Germany and Ukraine, was a theatre of World War II fought between the European Axis powers and Allies, including the Soviet Union (USSR) and Poland. It encompassed Central Europe, Eastern Europe, Northeast Europe (Baltics), and Southeast Europe (Balkans), and lasted from 22 June 1941 to 9 May 1945. Of the estimated 70–85 million deaths attributed to the war, around 30 million occurred on the Eastern Front, including 9 million children. The Eastern Front was decisive in determining the outcome in the European theatre of operations in World War II and is the main cause of the defeat of Nazi Germany and the Axis nations. Historian Geoffrey Roberts noted that "more than 80 percent of all combat during the Second World War took place on the Eastern Front".

The Axis forces, led by Germany, invaded the Soviet Union in Operation Barbarossa on 22 June 1941. Despite warnings and the deployment of Axis armies on his borders, Stalin refused to believe that Hitler would invade and forbade any defensive preparations. Thus the Soviets were caught completely unprepared. They were unable to halt deep Axis advances into Russia, which came close to seizing Moscow. However, the Axis failed to capture the city, and Hitler shifted his focus to the oil fields of the Caucasus the following year. German forces advanced into the Caucasus under Fall Blau ("Case Blue"), launched on 28 June 1942. The Soviets decisively defeated the Axis at the Battle of Stalingrad—the bloodiest battle in the war and arguably in all of history—making it one of the key turning points of the front. A second great Axis defeat, at the Battle of Kursk, crippled German offensive capabilities permanently and cleared the way for Soviet offensives. Several Axis allies defected to the Allies, such as Italy, Romania and Bulgaria. The Eastern Front concluded with the capture of Berlin, followed by the signing of the German Instrument of Surrender on 8 May, ending the Eastern Front and the war in Europe.

Anders' Army was the informal yet common name of the Polish Armed Forces in the East in the 1941–42 period, in recognition of its commander Władysław Anders. The army was created in the Soviet Union but, in March 1942, based on an understanding between the British, Polish, and Soviets, it was evacuated from the Soviet Union and made its way through Iran to Palestine. There it passed under British command and provided the bulk of the units and troops of the Polish II Corps (member of the Polish Armed Forces in the West), which fought in the Italian Campaign. Anders' Army is notable for having been primarily composed of liberated POWs and for Wojtek, a bear who had honorary membership.

The People's Army (AL; Polish: Armia Ludowa; [ˈar.mʲja luˈdɔ.va]) was a communist partisan force of the Polish Workers' Party (PPR) active in Occupied Poland during World War II from January to July 1944. It was created on the order of the Soviet-backed State National Council to fight against Nazi Germany and support the Red Army against the German forces in Poland.

The Armia Ludowa was formed from the Gwardia Ludowa ("People's Guard") to aid the creation of a pro-Soviet communist government in Poland and, along with the National Armed Forces, refused to join the structures of the Polish Underground State and Home Army. It participated in a number of uprisings and supported Red Army offensives through Poland. The Armia Ludowa became part of the new Polish People's Army of the Soviet Polish Armed Forces in the East after seven months of existence.