The coalition was buoyed by the news that Bavaria, a former French ally, agreed to join the Sixth Coalition according to the Treaty of Ried concluded just before the Battle of Leipzig. This allowed the coalition to threaten the overall military position of the French by moving a 45,000 - 50,000 Austro-Bavarian army, under the command of Karl Philipp von Wrede, into Napoleon's rear, occupying Würzburg in Franconia. The small French garrison of Würzburg did not try to resist and instead barricaded themselves at the local citadel, allowing the enemy to occupy the town without a fight. From Würzburg, Wrede moved towards the strategic city of Hanau, along one of Napoleon's main retreat routes. Wrede’s advance guard reached Hanau on 28 October and took possession of the city, blocking Napoleon’s route to Frankfurt. Although Wrede probably assumed that the main part of the French forces was retreating along a more northerly road to Coblenz and thus expected to face a force of only 20,000 men, he did entertain hopes that he would be able to play a major role in the defeat of Napoleon. He also believed that the French army was completely disorganised, which was not true, and was closely followed by the main coalition army, the "Army of Bohemia", which was in reality much further away and not really in close contact with Napoleon's forces.
