The Reserve Cavalry Corps or Cavalry Reserve of the "Grande Armée" was a French military unit that existed during the Napoleonic Wars. In 1805, Emperor Napoleon Bonaparte appointed Marshal Joachim Murat to command all the cavalry divisions that were not directly attached to the army corps. During the Ulm campaign, Murat led his horsemen in successfully hunting down many Austrian units that escaped the capitulation of Ulm, before fighting at Austerlitz in December 1805. Under Murat, the Cavalry Reserve played a prominent role in the destruction of the Prussian armies after the Battle of Jena-Auerstedt in 1806. Five dragoon divisions of the corps were employed in the Peninsular War starting in 1808 and placed under the overall command of Marshal Jean-Baptiste Bessières. The Cavalry Reserve was reassembled in 1809 to fight Austria with Bessières still in command. In 1812, the Reserve Cavalry Corps was split up into the I, II, III, and IV Cavalry Corps for the French invasion of Russia.