Napoleonic Wars: Napoleon's Grande Armée crosses the Neman river beginning the invasion of Russia.

The French invasion of Russia, also known as the Russian campaign, the Second Polish War, the Second Polish campaign, the Patriotic War of 1812, and the War of 1812, was begun by Napoleon Bonaparte to force Russian Empire back into the continental blockade of the United Kingdom. Napoleon's invasion of Russia is one of the best studied military campaigns in history and is listed among the most lethal military operations in world history. It is characterized by the massive toll on human life: in less than six months nearly a million soldiers and civilians died.On 24 June 1812 and the following days, the first wave of the multinational Grande Arme crossed the Niemen into Russia. Through a series of long forced marches, Napoleon pushed his army of almost half a million people rapidly through Western Russia, now Belarus, in an attempt to destroy the separated Russian armies of Barclay de Tolly and Pyotr Bagration who amounted to around 180,000220,000 at this time. Within six weeks, Napoleon lost half of the men because of the extreme weather conditions, disease and hunger, winning just the Battle of Smolensk. The Russian Army continued to retreat, under its new Commander in Chief Mikhail Kutuzov, employing attrition warfare against Napoleon forcing the invaders to rely on a supply system that was incapable of feeding their large army in the field.

The fierce Battle of Borodino, seventy miles (110 km) west of Moscow, was a narrow French victory that resulted in a Council at Fili. There Kutuzov decided not to defend the capital but to a general withdrawal to save the Russian army. On 14 September, Napoleon and his army of about 100,000 men occupied Moscow, only to find it abandoned, and the city was soon ablaze, instigated by its military governor. Napoleon stayed in Moscow for five weeks, waiting for a peace offer that never came. Because of the nice weather he left late, hoping to reach the magazines in Smolensk by a detour. Losing the Battle of Maloyaroslavets he was forced to take the same route as he came. In early November it began to snow, which complicated the retreat. Lack of food and winter clothes for the men, fodder for the horses, and guerilla warfare from Russian peasants and Cossacks led to greater losses. Again more than half of the men died on the roadside of exhaustion, typhus and the harsh continental climate. The Grande Arme had deteriorated into a disorganized mob, and the Russians could not conclude otherwise.

In the Battle of Krasnoi Napoleon was able to avoid a complete defeat. Meanwhile, he was almost without cavalry and artillery, and deployed the Old Guard for the first time. Although several retreating French corps united with the main army, when the Berezina was reached, Napoleon only had about 49,000 troops and 40,000 stragglers of little military value. On 5 December, Napoleon left the army at Smorgonie in a sledge and returned to Paris. Within a few days, 20,000 more perished from the bitter cold and louse-borne diseases. Murat and Ney, the new commanders continued, leaving more than 20,000 men behind in the hospitals of Vilnius. What was left of the main armies crossed the frozen Niemen and the Bug disillusioned.

Although estimates vary because precise records were not kept, numbers exaggerated and auxiliary troops not always counted, Napoleon's army entered Russia with more than 450,000 men, more than 150,000 horses, around 25,000 wagons and more than 1,250 pieces of artillery. Only 120,000 men survived (excluding early deserters); as many as 380,000 died in the campaign. Perhaps most importantly, Napoleon's reputation of invincibility was shattered.

The Napoleonic Wars (1803–1815) were a series of major global conflicts pitting the French Empire and its allies, led by Napoleon I, against a fluctuating array of European states formed into various coalitions. It produced a period of French domination over most of continental Europe. The wars stemmed from the unresolved disputes associated with the French Revolution and its resultant conflict. The wars are often categorised into five conflicts, each termed after the coalition that fought Napoleon: the Third Coalition (1805), the Fourth (1806–07), the Fifth (1809), the Sixth (1813–14), and the Seventh (1815).

Napoleon, upon ascending to First Consul of France in 1799, had inherited a republic in chaos; he subsequently created a state with stable finances, a strong bureaucracy, and a well-trained army. In December 1805 Napoleon achieved what is considered his greatest victory, defeating the allied Russo-Austrian army at Austerlitz. At sea, the British severely defeated the joint Franco-Spanish navy in the Battle of Trafalgar on 21 October 1805. This victory secured British control of the seas and prevented the invasion of Britain. Concerned about increasing French power, Prussia led the creation of the Fourth Coalition with Russia, Saxony, and Sweden, which resumed war in October 1806. Napoleon quickly defeated the Prussians at Jena and the Russians at Friedland, bringing an uneasy peace to the continent. The peace failed, though, as war broke out in 1809, with the badly prepared Fifth Coalition, led by Austria. At first, the Austrians won a stunning victory at Aspern-Essling, but were quickly defeated at Wagram, which was the bloodiest battle in history until the battle of Leipzig.

Hoping to isolate and weaken Britain economically through his Continental System, Napoleon launched an invasion of Portugal, the only remaining British ally in continental Europe. After occupying Lisbon in November 1807, and with the bulk of French troops present in Spain, Napoleon seized the opportunity to turn against his former ally, depose the reigning Spanish royal family and declare his brother King of Spain in 1808 as José I. The Spanish and Portuguese revolted with British support and expelled the French from Iberia in 1814 after six years of fighting.

Concurrently, Russia, unwilling to bear the economic consequences of reduced trade, routinely violated the Continental System, prompting Napoleon to launch a massive invasion of Russia in 1812. The resulting campaign ended in disaster for France and the near destruction of Napoleon's Grande Armée.

Encouraged by the defeat, Austria, Prussia, Sweden, and Russia formed the Sixth Coalition and began a new campaign against France, decisively defeating Napoleon at Leipzig in October 1813 after several inconclusive engagements. The Allies then invaded France from the east, while the Peninsular War spilled over into southwestern France. Coalition troops captured Paris at the end of March 1814 and forced Napoleon to abdicate in April. He was exiled to the island of Elba, and the Bourbons were restored to power. But Napoleon escaped in February 1815, and reassumed control of France for around one hundred days. After forming the Seventh Coalition, the allies defeated him at Waterloo in June 1815 and exiled him to the island of Saint Helena, where he died six years later.The Congress of Vienna redrew the borders of Europe and brought a period of relative peace. The wars had profound consequences on global history, including the spread of nationalism and liberalism, the rise of Britain as the world's foremost naval and economic power, the appearance of independence movements in Latin America and subsequent decline of the Spanish and Portuguese Empires, the fundamental reorganization of German and Italian territories into larger states, and the introduction of radically new methods of conducting warfare, as well as civil law. After the end of the Napoleonic Wars there was a period of relative peace in continental Europe, lasting until the Crimean War in 1853.