The Battle of Austerlitz, also known as the Battle of the Three Emperors, was one of Napoleon's greatest victories, where the French Empire effectively crushed the Third Coalition. On 2 December 1805 (20 November Old Style, 11 Frimaire An XIV, in the French Republican Calendar), a French army, commanded by Emperor Napoleon I, decisively defeated a Russo-Austrian army, commanded by Tsar Alexander I and Holy Roman Emperor Francis II, after nearly nine hours of difficult fighting. The battle took place near Austerlitz (Slavkov u Brna) about 10 km (6 mi) south-east of Brno in Moravia, at that time in the Austrian Empire (present day Czech Republic). The battle is often regarded as a tactical masterpiece.

The French victory at Austerlitz effectively brought the Third Coalition to an end. 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. Prussian worries about growing French influence in Central Europe sparked the War of the Fourth Coalition in 1806.