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.
Peace of Riga
The Russian Civil War presented an opportunity for Poland under the leadership of Józef Piłsudski to regain parts of the tsarist territories of the former Polish-Lithuanian Commonwealth which had been incorporated into the Russian Empire during the Partitions of Poland. Meanwhile, many in the Soviet leadership desired to respond to Piłsudski's moves into the Ukraine by using military force against Poland, which was seen by the Soviets as a land bridge to Western Europe, and thus to extend the revolution westwards. The Polish–Soviet War ensued, culminating in the Polish victory in the Battle of Warsaw (1920), after which both sides became receptive to ending the conflict. Further military setbacks following their defeat near Warsaw made the Soviets eager to begin peace treaty negotiations, and the Poles, pressured by the League of Nations, were also willing to negotiate after the Polish army had annexed most of the disputed territories in the war, but was nearing exhaustion.