Pierre de Meslon enlisted in the Saint-Cyr military academy as a volunteer in 1900. He entered the 13th Cuirassier Regiment as second lieutenant in 1903. One year later, he was transferred to the 4th Dragoon Regiment, where he was promoted to lieutenant in 1905. He returned to the 1st Cuirassier Regiment in 1911. At the 1912 Olympics, de Meslon was entered in dressage and jumping but did not compete. He was seconded to the Fontenay Remount Depot and rose to the rank of captain in 1915. One year later, he became purchasing officer of his division and was in charge of equipment of the 5th Dragoon Regiment from 1917. After World War I, he was involved in the occupation of the Rhineland and was in 1923 assigned to the 3rd Regiment of African Light Infantry in Algeria. Due to various physical disabilities, de Meslon was discharged in 1928.
France