Battle of Wagram

The Battle of Wagram (July 5–6, 1809) was one of the most important military engagements of the Napoleonic Wars and ended in a decisive victory for Emperor Napoleon I's French and Allied army against the Austrian army under the command of Archduke Charles of Austria-Teschen. The battle virtually spelled the destruction of the Fifth Coalition, the Austrian and British-led alliance against France.

In 1809, the French military presence in Germany was diminished, as Napoleon transferred a large 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 in a swift campaign 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 a massive army, with which he retreated north of the Danube. This allowed the Austrians to continue the war but, towards the end of May, Napoleon abruptly resumed the offensive and suffered a tactical defeat at the Battle of Aspern-Essling.

It took Napoleon six weeks to prepare his next offensive, for which he amassed a 165,000 man French, German and Italian army in the vicinity of Vienna. The Battle of Wagram began after Napoleon swiftly took the bulk of these forces across the Danube during the night of 4/5 July and attacked the 145,000-men strong Austrian army. Having successfully crossed the river, Napoleon attempted an early breakthrough and launched a series of violent, though ill-prepared evening attacks against the Austrian army. The latter was thinly-spread on a wide semicircle, but held a naturally strong position. After the attackers enjoyed some initial success, the tenacious 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 double envelopment. The offensive failed against the mighty French right but nearly shattered Napoleon's overstretched left. However, the Emperor masterfully countered by launching a violent 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 Maréchal Louis-Nicolas Davout drove a relentless offensive, turning the Austrian left, eventually rendering Charles's position untenable. Towards mid-afternoon on 6 July, Archduke Charles admitted defeat and led a timely and brilliant staged retreat, frustrating all enemy attempts to pursue. After the battle, Archduke Charles remained in command of a significant and still cohesive force and decided to retreat to Bohemia. However, the Grande Armée 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.

The two-day battle of Wagram was particularly bloody, mainly due to the extensive use of artillery on a flat battlefield packed with some 300,000 men. Despite the fact that Napoleon was the uncontested winner, he failed to secure a complete 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 Peace Treaty of Schönbrunn meant the loss of one sixth of the Austrian Empire's subjects, alongside significant territories.