Polish–Soviet War: The Battle of Radzymin concludes; the Soviet Red Army is forced to turn away from Warsaw.

The Polish–Soviet War was fought primarily between the Second Polish Republic and the Russian Soviet Federative Socialist Republic, following World War I and the Russian Revolution.

The Battle of Radzymin took place during the Polish–Soviet War (1919–21). The battle occurred near the town of Radzymin, some 20 kilometres (12 mi) north-east of Warsaw, between August 13 and 16, 1920. Along with the Battle of Ossów and the Polish counteroffensive from the Wieprz River area, this engagement was a key part of what later became known as the Battle of Warsaw. It also proved to be one of the bloodiest and most intense battles of the Polish–Soviet War.

The Workers' and Peasants' Red Army, often shortened to the Red Army, was the army and air force of the Russian Soviet Republic and, from 1922, the Soviet Union. The army was established in January 1918 by a decree of the Council of People's Commissars to oppose the military forces of the new nation's adversaries during the Russian Civil War, especially the various groups collectively known as the White Army. In February 1946, the Red Army was renamed the "Soviet Army". Following the dissolution of the Soviet Union it was split between the post-Soviet states, with its bulk becoming the Russian Ground Forces, commonly considered to be the successor of the Soviet Army.

Warsaw, officially the Capital City of Warsaw, is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland. Its population is officially estimated at 1.86 million residents within a greater metropolitan area of 3.27 million residents, which makes Warsaw the 6th most-populous city in the European Union. The city area measures 517 km² (200 sq mi) and comprises 18 districts, while the metropolitan area covers 6,100 km² (2,355 sq mi). Warsaw is classified as an alpha global city, a major political, economic and cultural hub, and the country's seat of government. It is also the capital of the Masovian Voivodeship.