In 1807 France tried to force Portugal to join the Continental System, a commercial embargo against Britain. When the Portuguese Prince Regent, John refused to join, Napoleon sent General Junot to invade Portugal in 1807, resulting in the six Year Peninsular War. After Austria was defeated in 1805, the nation spent three years reforming its army. Encouraged by the events in Spain, Austria sought another confrontation with France to avenge their defeats and regain lost territory and power. Austria lacked allies in central Europe. Austria and Prussia requested that Britain fund their military campaigns and requested a British military expedition to Germany. Austria received £250,000 in silver, with a further £1 million promised for future expenses. Britain promised an expedition to the low countries and to renew their campaign in Spain. After Prussia decided against war, the Fifth Coalition formally consisted of Austria, Britain, Portugal, Spain, Sicily and Sardinia, though Austria was the majority of the fighting effort. Russia remained neutral even though they were allied to France.

In the opening engagements of the war, Archduke John defeated the Franco-Italian army and drove it back to the Adige River at Verona. Forced to detach substantial forces to watch Venice and other enemy-held fortresses, John found himself facing a strongly reinforced Franco-Italian army near Verona. The outnumbered Austrians led by Archduke John of Austria successfully fended off the attacks against a Franco-Italian army headed by Eugène de Beauharnais, the Viceroy of the Kingdom of Italy. in actions at San Bonifacio, Soave, and Castelcerino before retreating to the east. ion. John knew that with Napoleon advancing on Vienna, his position in Italy could be flanked by enemy forces coming from the north. He decided to retreat from Italy and defend the borders of Austria in Carinthia and Carniola. After breaking all bridges over the Alpone, John began his withdrawal in the early hours of May 1, covered by Feldmarschallleutnant Johann Maria Philipp Frimont's rear guard.

Stralsund, a port at the Baltic Sea in Swedish Pomerania, was surrendered to France after the siege of 1807 during the War of the Fourth Coalition. During this war, Prussian captain Ferdinand von Schill distinguished himself by cutting off French supply lines using guerrilla tactics in 1806. In 1807, he raised a freikorps and successfully fought the French forces in what he intended to become a patriotic insurrection. In January and February 1809, the German resistance in French-held Westphalia invited Schill to lead an uprising. The Battle of Stralsund was fought between Ferdinand von Schill's freikorps and Napoleonic forces in Stralsund. In a "vicious street battle", the freikorps was defeated and Schill was killed in action.

The Walcheren Campaign was an unsuccessful British expedition to the Netherlands in 1809 intended to open another front in the Austrian Empire's struggle with France during the War of the Fifth Coalition. Sir John Pitt, 2nd Earl of Chatham, was the commander of the expedition, with the missions of capturing Flushing and Antwerp in the Netherlands and enabling navigation of the Scheldt River. Some 40,000 soldiers, 15,000 horses together with field artillery and two siege trains crossed the North Sea and landed at Walcheren on 30 July. This was the largest British expedition of that Year, larger than the army serving in the Peninsular War in Portugal. Nevertheless it failed to achieve any of its goals. The Walcheren Campaign involved little fighting, but heavy losses from the sickness popularly dubbed "Walcheren Fever".

Key Findings:

• Austria losses territory
• Austria also paid to France a large indemnity
• Austrian army limited to 150,000 troops
• Bavaria gains Salzburg, Berchtesgaden, and Innviertel
• Duchy of Warsaw gains Western Galicia
• Russia gains part of Eastern Galicia
• France gains Dalmatia & Trieste(Austria loses access to Adriatic Sea)
• Napoleon married the daughter of Emperor Francis, Marie Louise. Napoleon hoped the marriage would cement a Franco-Austrian alliance and provide legitimacy to his regime. The alliance gave Austria respite from war with France
• The revolts in Tyrol and the Kingdom of Westphalia during the conflict were an indication that there was discontent over French rule among the German population.
• The war undermined French military superiority and the Napoleonic image
• The Battle of Aspern-Essling was the first major defeat in Napoleon's career and was warmly greeted by much of Europe.