Final answer:
Napoleon invaded Russia in June 1812 with a grand army of 650,000 men. The Russian scorched earth policy, coupled with the onset of winter, diseases, and lack of supplies, led to catastrophic French losses. This defeat weakened Napoleon's power and led to the formation of a coalition that ultimately forced his abdication and exile.
Step-by-step explanation:
In June of 1812, Napoleon launched a massive invasion into Russia with his Grand Army, consisting of approximately 650,000 men. Despite initial successes, such as the capture of Vilna and entering Moscow to find it ablaze, the campaign was disastrous for the French. The Russian scorched earth policy, disease, lack of supplies, and the harsh winter decimated Napoleon's forces. By the time Napoleon began his retreat from Moscow, his army was severely reduced, and the campaign concluded with a devastating loss of life and the eventual retreat of only about 40,000 troops back to France. The failure of the invasion weakened Napoleon's dominance in Europe and led to the resurgence of a coalition against him. The events that unfolded after Napoleon's invasion altered the course of European history, leading to his abdication and eventual exile.
Napoleon's army faced the realities of war with inexperienced troops and logistical difficulties. The Battle of Borodino was particularly brutal, with heavy casualties on both sides. The disastrous French retreat marked a turning point, with attacks by Russian forces, rampant disease, and starvation significantly diminishing the Grand Army's numbers. This catastrophe for Napoleon led to the reformation of an anti-French coalition among European powers and set the stage for his first abdication and exile to Elba.