During 1642 to 1643, the regiment fought in the Reapers' War under Marshal Philippe de La Mothe-Houdancourt, helping gain large sections of the Principality of Catalonia for the French–Catalan alliance. It joined the Duke of Enghien in Germany in 1644, fighting at Freiburg, Phillippburg, Mainz, and Landau. At the Second Battle of Nördlingen on 3 August 1645, the Marquis de Livry was killed. The Marquis de Lanques replaced him, and under his command, the regiment was among those that took Heilbronn and Trier for the French. The regiment was sent to the siege of Dunkirk, where on 26 December 1646 it was renamed the "Régiment de Condé-Cavalerie", after Enghien became Prince of Condé on the death of his father. The "Condé-Cavalerie" was sent to Catalonia for two years, while Prince Louis was assigned to command the French and Catalan forces, where it took part in the unsuccessful second siege of Lleida.