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.
Battle of Mława
As a result of the Treaty of Versailles, the new German-Polish border was located only some 120 km north of Warsaw, the Polish capital city. In 1939 the Polish Modlin Army, led by Brigadier General Emil Krukowicz-Przedrzymirski, was thought of as the main defensive force guarding Polish borders from the north. It was located along the border with East Prussia and was to stop the enemy forces advancing towards Warsaw, the Modlin Fortress. Shortly before the war, a decision was made to strengthen the Polish defences by construction of a line of field fortifications and concrete bunkers to the north of Mława, in the centre of the army's positions.