In the Battle of Halle on 17 October 1806 a French corps led by Jean-Baptiste Bernadotte fought the Prussian Reserve under Eugene Frederick Henry, Duke of Württemberg. The French defeated their opponents, forcing the Prussians to retreat northeast toward Dessau after suffering heavy losses. The clash occurred in the War of the Fourth Coalition, part of the Napoleonic Wars. The city of Halle is located about 30 kilometers northwest of Leipzig on the Saale River.