War of The Third Coalition

The War of the Third Coalition was a European conflict spanning the years 1803 to 1806. During the war France and its client states under Napoleon I defeated an alliance of Austria, Portugal, Russia, and others.

Great Britain had already been at war with France following the resumption of hostilities resulting from the breakdown of the Peace of Amiens and remained the only country still at war with France after the Treaty of Pressburg. From 1803–05, Britain stood under constant threat of a French invasion. The Royal Navy, however, secured mastery of the seas and decisively destroyed a Franco-Spanish fleet at the Battle of Trafalgar in October 1805.

The Third Coalition itself came to full fruition as Napoleon's provocative actions in Italy, crowning himself King, and Germany spurred Austria into joining Britain and Russia against France. The war would be decided on the continent, and the major land operations that sealed the swift French victory involved the Ulm Campaign, a large wheeling manoeuvre by the Grande Armée lasting from late August to mid-October 1805 that captured an entire Austrian army, and the decisive French victory over a combined Russo-Austrian force under Tsar Alexander I at the Battle of Austerlitz in early December. Austerlitz effectively brought the Third Coalition to an end, although later there was a small side campaign against Naples, which also resulted in a decisive French victory at the Battle of Campo Tenese.

On 26 December 1805, Austria and France signed the Treaty of Pressburg, which took Austria out of both the war and the Coalition, while it reinforced the earlier treaties between the two powers of Campo Formio and of Lunéville. The treaty confirmed the Austrian cession of lands in Italy and Bavaria to France and in Germany to Napoleon's German allies, imposed an indemnity of 40 million francs on the defeated Habsburgs, and allowed the defeated Russian troops free passage, with their arms and equipment, through hostile territories and back to their home soil. Victory at Austerlitz also permitted the creation of the Confederation of the Rhine, a collection of German states intended as a buffer zone between France and central Europe. As a direct consequence of these events, the Holy Roman Empire ceased to exist when, in 1806, Holy Roman Emperor Francis II abdicated the Imperial throne, keeping Francis I of Austria as his only official title. These achievements, however, did not establish a lasting peace on the continent. Austerlitz had driven neither Russia nor Britain, whose armies protected Sicily from a French invasion, to settle. Meanwhile, Prussian worries about growing French influence in Central Europe sparked the War of the Fourth Coalition in 1806.