The IX Corps of the Grande Armée was the name of a French military formation that existed during the Napoleonic Wars. The corps was first formed in 1806 from German troops allied with the First French Empire and Emperor Napoleon appointed his brother Jerome Bonaparte as commander. During 1807, elements of the corps besieged several Prussian fortresses. The corps was revived as an all-Saxon unit in 1809 and leadership given to Marshal Jean-Baptiste Bernadotte. The corps fought at Linz-Urfahr and Wagram. In 1810, a new IX Corps appeared in Spain led by Jean-Baptiste Drouet, Comte d'Erlon. The corps was in action at the Battle of Fuentes de Onoro in 1811 before being discontinued. The corps was reformed in 1812 for the French invasion of Russia and Marshal Claude Perrin Victor assigned to lea