The Trachenberg Plan (12 July 1813) was the Allied plan for the Autumn Campaign of 1813 (War of Liberation), and called for each of the three Allied armies to avoid fighting Napoleon in person, but to threaten his communications and attack his Marshals, wearing down the French army and denying Napoleon the chance to win a decsisve victory.
Once it became clear that the Austrians would probably join the war against Napoleon work began on a plan for the Autumn campaign. The distribution and organisation of the Allied armies was one issue. After several plans were proposed it was decided to form three main Allied armies. Bernadotte would be given command of the Army of the North. A Prussian (eventually Blücher) would command the Army of Silesia, which had been the main army in the Spring Campaign, but would now be reduced in size. The main Allied force would be the Army of Bohemia, made up of the Austrian army, reinforced by a large part of the Army of Silesia. This force was to be commanded by Prince Schwarzenberg, an experienced officer and diplomat, but not perhaps the most able of commanders. All three Allied monarchs – Tsar Alexander, Frederick William III of Prussia, and Francis I of Austria – would accompany this army.
The second problem was to decide how to defeat Napoleon. On 9 July the Tsar, the King of Prussia, and Bernadotte (by now the Crown Prince of Sweden) met at Trachenberg (north of Breslau), and after three days of talks produced the famous Trachenberg plan. Several people later claimed credit for this idea, including Bernadotte, General Karl Freiherr Toll (one of many Prussians to have entered the Russian service) and the Prussian Hermann von Boyen.
The detailed work was carried out by Johann Joseph Wenzel Graf Radetzky von Radetz (Chief of Staff for Schwarzenberg), General Freidrich von Langenau (a Saxon, head of Austrian Operations Directorate) and their Allied counterparts.
Although the plan is best known for committing the Allies to deliberately avoiding battle with Napoleon, it was more sophisticated than that. The original version was actually less defensively minded.
Under the version of the plan agreed on 12 July at Trachenberg the overall Allied plan was to advance towards Napoleon's main army. Any Allied force that found itself on his flanks was to attack his communcations.
The Army of Bohemia, which was expected to be Napoleon's first target, was to take up a central position from where it could advance against Napoleon wherever he decided to move.
Around 100,000 men were to move from the Army of Silesia to the Army of Bohemia just before the end of the Armistice to make this the main army.
Bernadotte was to move south to threaten Leipzig.
Blücher was to follow the French if they retreated towards the Elbe, but not to risk an major battle unless he had a very strong position. Once he reached the Elbe Blücher was to join up with Bernadotte, or if that route was blocked, with Schwarzenberg.
The Army of Bohemia was given three possible routes of advance, taking it towards Silesia in the east, or into Saxony. A retreat towards the Danube was also considered. If Napoleon did advance into Bohemia, then Bernadotte was to move south as quickly as possible to attack Napoleon's rear.
If Napoleon moved north to attack Bernadotte, the other two armies would attack Napoleon's communications in an attempt to force him to fight against superior numbers.
The enemy's camp was to be the main objective of all Allied armies. This was a key element of the plan. In earlier campaigns Napoleon's opponents had often made the mistake of making some geographical location their objective, rather than the defeat of Napoleon's army. This time the French army was to be the main target.
This plan then had to go to Austria to be approved. The Austrians were less keen on risking a battle against Napoleon, and insisted that the plan be modified so that all three armies were instructed to avoid a battle against Napoleon. If any one of the three encountered the Emperor in person they were to retreat, while the other two would advance. Prussia and Russia agreed to these changes at Reichenbach on 19 July.
The plan was confirmed again later in the year at Teplitz, during the talks that led to the signing of the Treaty of Teplitz (9 September 1813).
The one possibility the Trachenberg plan didn't consider was what to do if Napoleon didn't go onto the offensive. When the Armistice ended in mid August Napoleon's plan was to wait for the Allies to move, and then defeat whichever Allied army seemed most vulnerable. Although Napoleon was soon moving east to deal with Blücher's Army of Silesia, this brief gap encouraged the Allied high command to risk a general offensive with the Army of Bohemia. This soon gave Napoleon the chance he wanted, and the resulting battle of Dresden (26-27 August 1813) was the closest he came to a decisive victory during the War of Liberation.
Elsewhere the wisdom of attacking Napoleon's marshals was demonstrated by the Allied victories at Grossbeeren (23 August), the Katzbach (26 August) and Kulm (29-30 August). During the War of Liberation Napoleon only lost one battle, at Leipzig, while his marshals hardly recorded any successes in independent command (Ney, Oudinot, Macdonald and Vandamme all suffered heavy defeats).
The final campaign that ended with the Allied victory at Leipzig didn't really follow the Trachenberg plan, with Blücher in particular pushing the Allies towards a concentration of all three of their armies, and a battle against an outnumbered Napoleon, but the circumstances that made this possible had been set up by the plan, which frustrated almost all of Napoleon's plans.