Battle of Warsaw (1920)
The battle of Warsaw was fought from August 12–25, 1920 as Red Army forces commanded by Mikhail Tukhachevsky approached the Polish capital of Warsaw and the nearby Modlin Fortress. On August 16, Polish forces commanded by Józef Piłsudski counterattacked from the south, disrupting the enemy's offensive, forcing the Russian forces into a disorganized withdrawal eastward and behind the Neman River. Estimated Russian losses were 10,000 killed, 500 missing, 30,000 wounded, and 66,000 taken prisoner, compared with Polish losses of some 4,500 killed, 10,000 missing, and 22,000 wounded.
Łódź Army
General Rómmel advanced with a small contingent of forces through towards Warsaw, where he assumed command of the improvised Warsaw Army tasked with defending the Polish capital (see siege of Warsaw), but he left most of his forces behind. General Wiktor Thommée assumed command of the remaining units. Piotrków Group, or as it became known after its commander, Thommée's Group, was much more successful, managing to avoid encirclement, and after the Battle of Wola Cyrusowa (September 8) his corps' last battle was the defence of the Modlin fortress (capitulated on 29 September).