The conviction that the continental system would be ruinous to her commerce, and that Napoleon would never rest until he had destroyed her influence as a first-rate European power, was soon forced on Russia, which had wrested Finland from Sweden in 1808, and extended her dominions to the Pruth, by the peace of Bucharest, concluded in 1812, after a six years' war with the Turks. The first coolness between Alexander and Napoleon was occasioned by the annexation of Galicia to the duchy of Warsaw, a measure which was regarded with suspicion by the Russian Emperor, as tending towards the reestablishment of Poland as a kingdom. Other causes of offense followed in rapid succession on the one side, Napoleon, who had already annoyed the Emperor by depriving the duke of Oldenburgh, husband of Alexander's aunt by the mother's side, of his dominions, now demanded the rigid enforcement of the continental system by Russia whilst, on the other, the union of Warsaw, as a province, with Saxony, and the evacuation of the Prussian dominions, were strongly urged on France by the Russian government. The refusal of each party to accede to the demands of the other, at length produced a war, which was commenced in 1812 by Napoleon, who collected an army of 400,000, or, according to some writers, 600,000 men, from almost every country in south-western Europe. To oppose this formidable armament, the Russians assembled 372,000 men. With his accustomed rapidity of movement, Napoleon cross ed the Nieman into Lithuania, and advanced by forced marches to Smolensk, with scarcely any opposition on the part of the Russians, who were unwilling to hazard a general engagement until they had formed a junction with the troops from the interior. After defeating the Russians at Smolensk, and Borodino, on the Moskwa, Napoleon, on the 14th of September, entered Moscow, which was entirely abandoned by the inhabitants, and soon after his arrival a fire broke out, occasioned probably by the Russian governor Rostopchin, which raged six days, and destroyed nine-tenths of the city. Notwithstanding this calamity, Napoleon lingered five weeks among the ruins of Moscow, endeavoring to negotiate a peace but discovering his error when it was too late, he broke up his quarters on the 18th of October, and commenced his retreat with an army now reduced to 104,000 men. The winter had already set in with a severity almost un precedented at that early season, and the whole of the country between Moscow and Beresina, an extent of 150 German miles, presented the appearance of a desert, the inhabitants of the villages having removed or destroyed all their agricultural produce. At length the army, reduced by famine and the unceasing attacks of the Russians and Cossacks to 30,000 men capable of bearing arms, reached the Beresina, where the passage of the river was forced by Ney and Oudinot, with 8,500 men, in the face of 25,000 Russians. The retreat now became a flight, in consequence of the intensity of the cold, and the abandonment of the army by Napoleon, who had placed himself in a sledge, when all was lost, and proceeded to Paris (arrived 18th December,) where his presence was rendered necessary by the unsettled state of public affairs. General Ney, who had distinguished himself in the battle of the Moskwa, and done good service by the masterly manner in which he had conducted the retreat, was created Prince of the Moskwa. The first step towards the emancipation of Prussia, was the conclusion of a convention of neutrality between the Prussian general Diebitsch and general York, who was sent to cover the retreat of the left wing of the French army under Macdonald. This proceeding on the part of the Prussian general was stigmatized by Napoleon as an act of the grossest treachery, and the chief cause of his subsequent misfortunes.
Frederick William III of Prussia, after issuing from Breslau a manifesto, in which he called on his people to rise and defend their liberties against the encroachments of the French, now concluded an affiance with Russia for the reestablishment of the Prussian monarchy, and having been subsequently joined by Sweden and England, commenced his preparations for the formation of a national militia in Prussia.
In the month of March, the Prussian grand army under Blucher, marched through Silesia to Dresden, where it awaited the arrival of a Russian force commanded by Kalish. A second Russo-Prussian army was also sent from Berlin to join the two other corps. The allied army, under Wittgenstein, now numbered 85,000 men, and that of the French 120,000, most of whom were raw conscripts.