The Battle of Fontenoy, May 11, 1745 Detail on the King Louis XV, his staff and his son

As a regular painter of the king, Lenfant was recruited in 1746 by Count Marc-Pierre de Voyer d'Argenson (1696–1764), Secretary of State during the 1743–1757 War, as illustrator of His Majesty's camps and armies. He was tasked with completing a series of battle paintings for the Hôtel d'Argenson in Neuilly. This series was duplicated with some significant variations for the offices in the Hôtel de la Guerre in Versailles.
The painting found in the Musée de l'Armée is from the Neuilly series, transferred from the Ormes family assets in Poitou following the fall from grace of the Count of Argenson. The composition aligns with the theme showcased by Adam van der Meulen (1632–1690) during the previous century: the king is depicted in gray attire, followed by the heir apparent in red attire and surrounded by the royal staff officer. The royal figure dominates the battlefield, where the main action takes place. He is visible from a cavalry perspective, namely the disruption of the Anglo-Hanoverian line under the combined attacks of the French cavalry and infantry. This stunning victory, called "the most glorious day since the Battle of Bouvines," was celebrated by Voltaire in 1745. It resulted in significant losses, as witnessed by the Duke of Croÿ (1718–1784), commander of the Royal-Roussillon cavalry. It was also the first—since that of Poitiers in 1356—and last battle of the Ancien Régime over which the King and his son presided in person. Suffering from acute edema, the Marshal de Saxe led the combat, which he himself organized and strategized, from his campaign carriage, as depicted by Lenfant.