The military preparations of the French army were completed in March 1812.
The "Great army", assigned for a campaign to Russia, was composed of 647 thousand persons and 1372 guns. Huge warehouses and transports were prepared. French were only half of that army, into which entered the representatives of the nations won by Napoleon.
The 448-thousand grouping was the first echelon of the French forces, which entered the Russian territory. "The great army" was headed by Napoleon; among his marshals were L.Davu, M.Nei, I.Murat, U.Ponyatovsky.
At the western border of Russia were standing 214 thousand persons divided into three armies and three corps: the first army under M.B.Barklai De Tolli's command (120210 persons) was in the area of Vilno, covering the Petersburg's direction; the 2nd army (49 423 persons), in the area of Belostok, in the Moscow direction; the 3rd army (44 180 persons) in Lutsk, in the Kiev direction; near Riga was the corps of N.N.Essen (38 077 persons), two more corps were standing in reserve at the second line. The corps of F.F.Steingel in Finland and P.V.Chichagov's Danube army in the south covered flanks and did not take part in military operations at the beginning of the war.
The moral spirit of the Russian army was extremely high. Apart brilliant military leaders Barklai De Tolli and Bagration, the armies were commanded by talented generals D.S.Dokhturov, A.P.Ermolov, P.P.Konovnitsyn, M.I.Platov, N.N.Raevsky etc. Barklai De Tolli, being the military minister, became the Commander-in-chief of the army.
The 12th of June 1812 Napoleon crossed Neman and entered the Russian territory. He expected to surround and break two Russian armies but Barklai, following his plan, began a deviation, moving to the connection with the army of Bagration and making rearguard fights. The 22nd of July Russian armies were unified in Smolensk. Having repulsed series of attacks of the French army, the Russian armed forces, the 6th of August, under the command of Barklai De Tolli continued to retreat. The plan of Napoleon, intending to crush Russian armies separately in frontier battles and to compel Russia to the conclusion of peace on his conditions, fell. The war was delayed, the losses of "Great army" grew, its supply worsened. On the occupied grounds the wave of the guerrillas movement rose. From Smolensk, Napoleon sent to Alexander I a peace proposition, but did not receive the answer. Napoleon continued the approach to Moscow following Russian armies hoping for decisive battle.
The unsatisfaction due to the long retreat and the growing mistrust of Barklai De Tolli in the army and generally in the Russian society forced the emperor, the 8th of August, to appoint as commander-in-chief M.I.Kutuzov, an experienced and cautious commander. Kutuzov started the preparation for the decisive battle, for which the Russian army receded at the position near the village of Borodino, in 110 versts from Moscow. There, on the 26th of August (the 7th of September) took place the battle that played a decisive role on the issue of the war.
After a fight proceeding all the day, Frenchmen (133800 persons, 587 weapons) could occupy the positions of the Russian army (154800 persons, including about 30000 civil guardsmen, 640 weapons), but did not crush it. The losses of the French Army were estimated at 28 thousand, Russian - 45,6 thousand persons. Napoleon managed to save its reserves (20 thousand); the reserves of the Russian army almost exhausted. Kutuzov could not crush the French army nor stop its approach; but despite of heavy losses, the Russian army was rescued and could continue its campaign.
The 27th of August, Kutuzov gave the order to continue the retreat in the direction of Moscow. Napoleon, hoping for new battle, was moving after. The 1st of September, at the military council situated in a village near Moscow Fili, Kutuzov took up the responsibility for the heavy decision about the leaving of the ancient capital without fight for the sake of the army. Leaving the city, Kutuzov and the Moscow general-governor F.Rostopchin ordered to burn warehouses. The 2nd of September, Napoleon entered Moscow left by inhabitants, and in the evening the city burst into fire in different places. The fire that covered all Moscow, destroyed stocks of the foodstuffs and arms; 70% of buildings burned. Three times Napoleon proposed to Alexander I to start peace talks, but he did not answer him. Napoleon could not stay in the devastated city during the winter; that is why Napoleon and the French Army left Moscow on the 7th of October.
Kutuzov, camping in Tarutino, near Moscow, was preparing for a counterattack. The 6th of October, Kutuzov began a counterattack against the army of Napoleon, expecting to go to the winter apartments at the western border of Russia. The 12th of October 1812, as result of a bloody battle in Maloyaroslavets, Napoleon was compelled to recede along the ruined Mozhaisk's road to Smolensk. Famine, strong frosts, constant impacts of the Russian army on the French army transformed their retreat into flight. But it was not possible to completely destroy the former "Great army".
Napoleon guessed the plan of Кuтuzov to surround the French army at the river Berezina, built a false passage and the 14th-16th of November passed the river in another place, lost 50 thousand persons, but saved marshals, generals and its guards (9 thousand people). The 23rd of November Napoleon abandoned the rests of the army and secretly left for Paris. The 28th of November, Russian armies finished their counterattack, and the 25th of December 1812, Alexander's I manifest announced the final expulsion of the aggressors from the territory of Russia and the victorious end of the patriotic war.