Captain Calès entered on Year II (during the reign of Terror), the Army of the Eastern Pyrenees, formed by the Convention after the invasion of France by the Kingdom of Spain in April 1793 in retaliation for the execution of King Louis XVI of France just three months before. Calès particularly distinguished himself the 27 Brumaire Year III (17 November 1794) at the Battle of the Black Mountain ("also called" "Battle of the" "Sierra Negra") against the allied armies of the kingdoms of Spain and Portugal: at the head of two companies of Chasseurs, captain Calès overthrew 800 Spaniards. General Jacques François Dugommier died during the battle, but he defeated the allied armies. The famous surgeon Larrey also distinguished himself during this battle practicing in one day not less than 200 amputations. This decisive French victory led to the capture of Figueres, then to the victorious Siege of Roses and to the escape of the Spanish troops by sea, and finally to the signature of the Peace of Basel between France and Prussia (April 5, 1795) and between France and Spain (July 22, 1795 - 4 Thermidor Year III), by which the two countries signed peace with the victorious revolutionary France, thus abandoning the First Coalition. However, Calès got wounded during the blockade of Figueres on November, 29 by the explosion of a gunpowder magazine.