In the Army of the Eastern Pyrenees and in the Army of the Moselle he repeatedly distinguished himself for valour, and in 1796, as captain, he served in Napoleon Bonaparte's Italian campaign. At Roveredo his conduct brought him to his chief's notice, and after the Battle of Rivoli he was sent to France to deliver the captured colours to the Directory. Hastening back to the front, he accompanied Napoleon in the invasion of Styria in command of the "Guides," who formed the nucleus of the later Consular and Imperial Guard.
Returning to Europe with Napoleon, he was present at Marengo (1800) as second-in-command of the Consular Guard, and led a brilliant and successful cavalry charge at the close of the day, though its effect on the battle was not as decisive as Napoleon pretended.
Promoted general of division in 1802 and marshal of France in 1804, he made the most famous campaigns of the Grande Armée as colonel-general of the Guard Cavalry (1805, 1806, 1807). In 1805 he had received the Grand Eagle of the Legion of Honour, and in 1809 was created duke of Istria.
With the outbreak of the Peninsular War, Marshal Bessières had his first opportunity of an independent command, and his crushing victory over the Spaniards at Medina del Rio Seco (1808) justified Napoleon's choice. When disaster in other parts of the theatre of war called Napoleon himself to the Peninsula, Bessiêres continued to give the emperor the very greatest assistance in his campaign. In 1809 he was again with the Grande Armée in the Danube valley. At Essling his repeated and desperate charges checked the Austrians in the full tide of their success. At the Battle of Wagram he had a horse killed under him. Replacing Bernadotte in the command of the Army of the North, a little later in the same year, the newly-created duke of Istria successfully opposed the British Walcheren expedition, and in 1811 he was back again, in a still more important command, in Spain. As Masséna's second-in-command he was present at the battle of Fuentes d'Onoro, but Napoleon never detached him for very long, and in 1812 he commanded the Guard Cavalry at the Battle of Borodino and in the retreat from Moscow. Wherever engaged he won further distinction, and at the beginning of the 1813 campaign he was appointed to the command of the whole of Napoleon's cavalry.
Three days after the opening of the campaign, while reconnoitering the defile of Poserna-Rippach, Bessières was killed by a musket-ball. Napoleon, who deeply felt the loss of one of his truest friends and ablest commanders, protected his children, and his eldest son was made a member of the Chamber of Peers by Louis XVIII.
As a commander, especially of cavalry, Bessières left a reputation excelled by very few of Napoleon's marshals, and his dauntless courage and cool judgment made him a safe leader in independent command. He was personally beloved to an extraordinary extent amongst his soldiers, and (unlike most of the French generals of the time) amongst his opponents. It is said that masses were performed for his soul by the priests of insurgent Spain, and the king of Saxony raised a monument to his memory.
See also: Napoleonic Era