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.
Duchy of Warsaw
The duchy's armed forces were completely under French control via its war minister, Prince Józef Poniatowski, who was also a Marshal of France. In fact, the duchy was heavily militarized, bordered as it was by Prussia, the Austrian Empire, and Russia, and it was to be a significant source for troops in various campaigns of Napoleon.