“Victory belongs to the most persevering.”
Napoleon Bonaparte

Archduke Charles, German Erzherzog Karl, (born Sept. 5, 1771, Florence [Italy]—died April 30, 1847, Vienna, Austria), Austrian archduke, field marshal, army reformer, and military theoretician who was one of the few Allied commanders capable of defeating the French generals of the Napoleonic period. He modernized the Austrian army during the first decade of the 19th century, making it a formidable fighting force that contributed materially to Napoleon’s defeat in 1813–15.

The War of the Fifth Coalition was a European conflict in 1809 that was part of the Napoleonic Wars and the Coalition Wars. The main conflict took place in central Europe between the Austrian Empire of Francis I and Napoleon's French Empire. The French were supported by their client states—the Kingdom of Italy, the Confederation of the Rhine and the Duchy of Warsaw. Austria was supported by the Fifth Coalition which included the United Kingdom, Portugal, Spain, and the Kingdoms of Sardinia and Sicily, although the latter two took no part in the fighting. By the start of 1809 much of the French army was committed to the Peninsular War against Britain, Spain and Portugal. After France withdrew 108,000 soldiers from Germany, Austria attacked France to seek the recovery of territories lost in the 1803–1806 War of the Third Coalition. The Austrians hoped Prussia would support them as their former ally, but Prussia chose to remain neutral.

On 10 April 1809 Austrian forces under Archduke Charles crossed the border of Bavaria, a French client state. The French response, under Louis-Alexandre Berthier, was disorganised but order was imposed with the arrival of Napoleon on 17 April. Napoleon led an advance to Landshut, hoping to cut off the Austrian line of retreat and sweep into their rear. Charles crossed the Danube at Regensburg, which allowed him to retreat eastwards, although he failed to reach the Austrian capital, Vienna, before the French. A French assault across the Danube was repulsed on 21–22 May at the Battle of Aspern-Essling but a repeat attack was successful in July. Napoleon won a major victory at the 5–6 July Battle of Wagram, which forced the Austrians to sign the Armistice of Znaim on 12 July. Austrian invasions of the Duchy of Warsaw and Saxony (where they fought alongside the Black Brunswickers) were repulsed and they were driven out of their territories in Italy. British forces landed in Walcheren, in the French client state of Holland, but were unable to seize their objective of capturing Antwerp and were later withdrawn.

The war ended with the Treaty of Schönbrunn, which was regarded as harsh towards Austria as she lost her Mediterranean ports and 20% of her population. Despite the eventual French victory, their defeat at Aspern-Essling showed that Napoleon could be defeated on the battlefield. The war led to the Tyrolean Rebellion, the 1809 Gottscheer rebellion and rebellions in Italy which, although suppressed, foreshadowed future nationalist and anti-French risings. After Schönbrunn, Austria became a French ally and this was cemented by the marriage of Napoleon to the Austrian princess Marie Louise.