Napoleon’s Grande Armée began its failed invasion of Russia when it crossed the Neman River in what Russians refer to as the Patriotic War of 1812.
Russia had upset Napoleon by withdrawing from the Continental System, a French-led embargo against trade with Britain, in 1810. Meanwhile the Russian Tsar, Alexander I, was concerned by the formation of the Grand Duchy of Warsaw to the south. Napoleon consequently led his army across the Neman River in an attempt to secure Poland from the threat of a Russian invasion, and to force the Tsar to once again cease trading with Britain.
Up to 650,000 French soldiers invaded Russian Poland on 24 June for what Napoleon hoped would be a quick victory. The Grande Armée made significant progress into the Russian interior, forcing the Tsar’s vastly outnumbered forces back into Lithuania, but erratic weather conditions made the advance difficult. Supply wagons struggled on muddy tracks caused by thunderstorms while the troops were affected by sunstroke and disease in the hot and humid swamp-like conditions.
The retreating Russians also adopted scorched-earth tactics that destroyed farmland and villages, making it increasingly difficult for Napoleon to feed his army. Despite the problems this caused, the French successfully advanced for almost three months before reaching Moscow. The city had been evacuated, and Napoleon’s hopes of agreeing a peace treaty with Alexander were not realised.
Realising that his troops could not survive the winter, Napoleon led his army out of Moscow at the end of October. However, his numbers were seriously depleted and by December an estimated 380,000 men had died while another 100,000 had been captured.