Given free passage to Spanish territory, he was made governor of Rocroi and later fought in the 1656 Battle of Valenciennes, a crushing defeat inflicted by Condé on a French army led by Turenne. The 1659 Treaty of the Pyrenees that ended the war with Spain was delayed until Mazarin agreed to allow Montal and Condé to return home unpunished. Neither of them was trusted with a military command until the 1667-1668 War of Devolution; Montal served with Condé when he over-ran Franche-Comté in 1668, although it was returned to Spain in the Treaty of Aix-la-Chapelle.