With a Grand Armee of over 500,000, including contingents from Saxony, Prussia, Austria, the Grand Duchy of Warsaw; and from as far away as Portugal, Napoleon Bonaparte crosses the Nieman River and invades Russia. His initial plans, to force battle on the Imperial Russian Army by pinning against the approaches to St. Petersburg fails when the Russian abandon that city and move the capital to Moscow. The French are then obliged to follow the Russians east, along the Minsk - Smolensk - Moscow axis. By abandoning St. Petersburg, the Russians have bought themselves time.
One battle, Borodino, fought on the approaches to Moscow results in a French victory, albeit a Pyrrhic victory. Losses are heavy, and victory requires the deployment of the Old Guard. But Napoleon does succeed in taking [an abandoned] Moscow. While Czar Alexander strings him along, and kills more time, Napoleon lingers, forgetting his own maxim, "Ask me anything, except time". Moscow is then set ablaze by released prisoners, and in October, with the weather turning, Napoleon is forced to abandon the city.
Napoleon's plan is to strike south, then west and retreat through Ukraine. The Russians bock the move, offering battle. Napoleon then makes a disasterous decision, and changes his line of march back the way he had come to Moscow. With the worst winter in decades, he was now withdrawing through a countryside his troops had picked clean on their way TO Moscow. And picked clean included not only provender [like most armies of the age, the French lived off the land], but also shelter [huts had been used for cooking fires.
Fearing unrest in France, Napoleon left his army to his generals at Smolensk and returned to Paris. Dogged by Cossacks and other brigands, as well as some Russian units, the French army withdrew and fell apart.
By the time the last man crossed back into Poland [Marshal Ney], Napoleon had lost the great bulk of his army through starvation, freezing, capture, desertion [the entire Prussian contingent went over to the Russians. Of equal, if not more importance, he had lost some 500,000 horses, destroying the prowess of his cavalry, and the ability to move his artillery, a Napoleonic strong suit.
Napoleon would spend 1813 fighting a coalition [Prussia, Austria, Russia, Sweden and others] in Germany. In 1814, he would be fighting them, and Britain, in France. Then even his Marshals turned on him, and he was forced into exile on Elba. A return in 1815 led to the "100 Days", Waterloo, a second surrender, and to exile and death on the island of St. Helena in the South Atlantic. And it all started at the Nieman River.
