Due to the growing disagreements in the foreign policy of Russia and its actual refusal to support the continental trade blockade of England, Emperor Napoleon made, as it seemed to him, the only possible decision - to unleash military actions on the territory of Russia and force her to unconditionally follow the French course towards England.
The number of the combined troops of the French army for the campaign against Russia was 685,000, the border with Russia crossed 420,000. It included the troops of Prussia, Austria, Poland and the Countries of the Rhine Union.
As a result of the military campaign, Poland was to receive the territory of modern Ukraine, Belarus and part of Lithuania. Prussia retreated the territory of present-day Latvia, partly Lithuania and Estonia. In addition, France wanted help from Russia in the campaign against India, which at that time was the largest British colony.
On the night of June 24, according to the new style, the advanced units of the Great Army crossed the Russian border in the area of the Neman River. The guard Cossack units retreated. Alexander I made a last attempt to conclude a peace agreement with the French. In a personal message from the Russian Emperor to Napoleon, there was a demand to clear the Russian territory. Napoleon responded to the emperor with a categorical refusal in an insulting manner.
Already at the beginning of the campaign, the French had their first difficulties - interruptions in fodder, which led to a massive death of horses. The Russian army under the leadership of Generals Barclay de Tolly and Bagration, due to the large numerical advantage of the enemy, was forced to retreat inland, without giving a general battle. At Smolensk 1 and 2, the Russian armies united and stopped. On August 16, Napoleon ordered the start of the assault on Smolensk. After a fierce battle that lasted 2 days, the Russians blew up the powder magazines, set Smolensk on fire and retreated to the east.
The fall of Smolensk gave rise to a murmur of the entire Russian society against the commander-in-chief Barclay de Tolly. He was accused of treason, the surrender of the city: "The minister is taking the guest straight to Moscow" - they wrote with malice from Bagration's headquarters to St. Petersburg. Emperor Alexander decided to replace the commander-in-chief, General Barclay, with Kutuzov. Arriving in the army on August 29, Kutuzov, to the surprise of the whole army, gave the order to retreat further east. Taking this step, Kutuzov knew that Barclay was right, that Napoleon would be destroyed by a long campaign, the remoteness of troops from supply bases, etc., but he knew that the people would not allow him to give Moscow away without a fight. Therefore, on September 4, the Russian army stopped near the village of Borodino. Now the ratio of the Russian and French armies was almost equal: 120,000 men and 640 guns at Kutuzov and 135,000 soldiers and 587 guns at Napoleon.
On August 26 (September 7), 1812, according to historians, the turning point of the entire Napoleonic campaign came. The battle of Borodino lasted about 12 hours, losses on both sides were colossal: Napoleon's army lost about 40,000 soldiers, Kutuzov's army about 45,000. Despite the fact that the French managed to push back the Russian troops and Kutuzov was forced to retreat to Moscow, the Borodino battle was virtually lost did not have.
On September 1, 1812, a military council was held in Fili, at which Kutuzov took responsibility and ordered the generals to leave Moscow without a fight and retreat along the Ryazan road. The next day, the French army entered empty Moscow. At night, Russian saboteurs set fire to the city. Napoleon had to leave the Kremlin and give the order to partially withdraw his troops from the city. In a few days, Moscow burned down almost to the ground.
Partisan detachments, led by commanders Davydov, Figner and others, destroyed food warehouses, intercepted carts with fodder on the way of the French. Famine began in the Napoleonic army. The Kutuzov army turned from the Ryazan direction and blocked the approach to the Old Kaluga road, along which Napoleon expected to pass. This is how Kutuzov's ingenious plan "to force the Frenchman to retreat along the Old Smolensk road" worked.
Exhausted by the coming winter, hunger, loss of guns and horses, the Great Army suffered a crushing defeat at Vyazma on November 3, during which the French lost about 20 thousand more people. In the Battle of the Berezina that followed on November 26, the Napoleonic army was reduced by another 22,000. On December 14, 1812, the remnants of the Great Army crossed the Neman, and then retreated to Prussia. Thus, the Patriotic War of 1812 ended with a crushing defeat for Napoleon Bonaparte's army.