Napoleonic Wars - War of The Third Coalition 1805

War of The Third Coalition 1805

As Britain was gathering the Third Coalition against France, Napoleon planned an invasion of Great Britain, and massed 180,000 effectives at Boulogne. However, in order to mount his invasion, he needed to achieve naval superiority—or at least to pull the British fleet away from the English Channel. A complex plan to distract the British by threatening their possessions in the West Indies failed when a Franco-Spanish fleet under Admiral Villeneuve turned back after an indecisive action off Cape Finisterre on 22 July 1805. The Royal Navy blockaded Villeneuve in Cádiz until he left for Naples on 19 October; the British squadron subsequently caught and overwhelmingly defeated his fleet in the Battle of Trafalgar on 21 October (the British commander, Lord Nelson, died in the battle). Napoleon would never again have the opportunity to challenge the British at sea. By this time, however, Napoleon had already all but abandoned plans to invade Britain, and had again turned his attention to enemies on the Continent. The French army left Boulogne and moved towards Austria.

In April 1805, the United Kingdom and Russia signed a treaty with the aim of removing the French from the Batavian Republic (roughly present-day Netherlands) and the Swiss Confederation (Switzerland). Austria joined the alliance after the annexation of Genoa and the proclamation of Napoleon as King of Italy on 17 March 1805. Sweden, which had already agreed to lease Swedish Pomerania as a military base for British troops against France, formally entered the coalition on 9 August.

The Austrians began the war by invading Bavaria with an army of about 70,000 under Karl Mack von Leiberich, and the French army marched out from Boulogne in late July 1805 to confront them. At Ulm (25 September – 20 October) Napoleon surrounded Mack's army, forcing its surrender without significant losses. With the main Austrian army north of the Alps defeated (another army under Archduke Charles manoeuvred inconclusively against André Masséna's French army in Italy), Napoleon occupied Vienna. Far from his supply lines, he faced a larger Austro-Russian army under the command of Mikhail Kutuzov, with the Emperor Alexander I of Russia personally present. On 2 December, Napoleon crushed the joint Austro-Russian army in Moravia at Austerlitz (usually considered his greatest victory). He inflicted a total of 25,000 casualties on a numerically superior enemy army while sustaining fewer than 7,000 in his own force.

Austria signed the Treaty of Pressburg (26 December 1805) and left the Coalition. The Treaty required the Austrians to give up Venetia to the French-dominated Kingdom of Italy and the Tyrol to Bavaria.

With the withdrawal of Austria from the war, stalemate ensued. Napoleon's army had a record of continuous unbroken victories on land, but the full force of the Russian army had not yet come into play.