The Battle of Wagram ([varam]; 56 July 1809) was a military engagement of the Napoleonic Wars that ended in a costly victory for Emperor Napoleon's French and allied army against the Austrian army under the command of Archduke Charles of Austria-Teschen. The battle led to the breakup of the Fifth Coalition, the Austrian and British-led alliance against France. Wagram was the largest battle in European history up to its time.

In 1809, the French military presence in the Confederation of the Rhine was diminished as Napoleon transferred a number of soldiers to fight in the Peninsular War. As a result, the Austrian Empire saw its chance to recover some of its former sphere of influence and invaded the Kingdom of Bavaria, a French ally. Recovering from his initial surprise, Napoleon beat the Austrian forces and occupied Vienna at the beginning of May 1809. Despite the string of sharp defeats and the loss of the empire's capital, Archduke Charles salvaged an army, with which he retreated north of the Danube. This allowed the Austrians to continue the war. Towards the end of May, Napoleon resumed the offensive, suffering a surprise defeat at the Battle of Aspern-Essling.

It took Napoleon six weeks to prepare his next offensive, for which he amassed a 172,000-man French, German and Italian army in the vicinity of Vienna. The Battle of Wagram began after Napoleon crossed the Danube with the bulk of these forces during the night of 4 July and attacked the 136,000-man strong Austrian army. Having successfully crossed the river, Napoleon attempted an early breakthrough and launched a series of evening attacks against the Austrian army. The Austrians were thinly spread in a wide semicircle, but held a naturally strong position. After the attackers enjoyed some initial success, the defenders regained the upper hand and the attacks failed. Bolstered by his success, the next day at dawn Archduke Charles launched a series of attacks along the entire battle line, seeking to take the opposing army in a double envelopment. The offensive failed against the French right but nearly broke Napoleon's left. However, the Emperor countered by launching a cavalry charge, which temporarily halted the Austrian advance. He then redeployed IV Corps to stabilise his left, while setting up a grand battery, which pounded the Austrian right and centre. The tide of battle turned and the Emperor launched an offensive along the entire line, while Marchal Louis-Nicolas Davout drove an offensive, which turned the Austrian left, and rendered Charles's position untenable. Towards mid-afternoon on 6 July, Charles admitted defeat and led a retreat, frustrating enemy attempts to pursue. After the battle, Charles remained in command of a cohesive force and decided to retreat to Bohemia. However, the Grande Arme eventually caught up with him and scored a victory at the Battle of Znaim. With the battle still raging, Charles decided to ask for an armistice, effectively ending the war.

With 74,000 casualties, the two-day battle of Wagram was particularly bloody, mainly due to the use of 1,000 artillery pieces and the expenditure of 200,000 rounds of artillery ammunition on a flat battlefield packed with some 300,000 men. Although Napoleon was the uncontested winner, he failed to secure an overwhelming victory and the Austrian casualties were only slightly greater than those of the French and allies. Nonetheless, the defeat was serious enough to shatter the morale of the Austrians, who could no longer find the will to continue the struggle. The resulting Treaty of Schnbrunn meant the loss of one sixth of the Austrian Empire's subjects, along with some territories, rendering it landlocked until the German Campaign of 1813.

After the battle, Emperor Napoleon bestowed to Louis-Alexandre Berthier, who was his Marshal, Chief of Staff, Minister of War and Vice-Constable of the Empire, the victory title of 1st Prince of Wagram, making him an official member of the French nobility. Berthier had previously been granted the title of Sovereign Prince of Neuchtel and the Prince of Valangin in 1806. This allowed his descendants to carry the titles of Prince and Princess of Wagram.

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.