De Mortanges was the son of Sophia Kol from the family of Bank Vlaer & Kol financiers and Charles Ferdinand Pahud de Mortanges, a military officer overseeing the Dutch colonies. He and his elder sister were raised by their mother, after their father died in 1903. From early ages, de Mortanges was fascinated with horse riding and military, and in 1915 was accepted to the Royal Military Academy. After graduating with honors on 12 August 1918 he was assigned to The Hague regimen, where in 1919 he became a horse riding instructor. In 1922 he was noticed by K.F. Quarles van Ufford who headed the sports section of the Dutch military. Van Ufford became his mentor and enlisted him to the riding school of the Dutch cavalry in Amersfoort, where de Mortanges later worked as instructor between July 1925 and October 1927. In 1924 he was selected for the national Olympic team.
Olympic career
In 1924 de Mortanges won the gold medal in the team three-day event and placed fourth in the individual three-day event. Four years later he won the gold medals in the team three-day event as well as in the individual three-day event. In 1932 he won again the gold medal in the individual three-day event and the silver medal in the team three-day event. At the 1936 Summer Olympics he finished out of medals at the individual and team three-day events.
Later life
Besides the Olympics, between 1924 and 1936 de Mortanges took part in various international competitions and acted as a riding instructor with the Dutch cavalry. In 1938 he severely injured his right wrist in a riding accident, which halted his military and riding career. In 1942 he became a German prisoner of war. He escaped in Summer 1943 during a train transfer, and, after traveling through the occupied Belgium and France to Gibraltar, in February 1944 was flown to England. The same year, upon advice of his admirer Prince Bernhard, de Mortanges became a leading officer of the Royal Netherlands Motorized Infantry Brigade and later participated in the Normandy landings and liberation of the Netherlands. After the war de Mortanges returned to sport events. On 6 July 1946 he became president of the Dutch Olympic Committee, and remained in this position until 7 April 1961, with a break between 1951 and 1958 when he acted as a vice-president. He was also a member of the InternationalOlympic Committee between 4 September 1946 and 7 October 1964. In parallel, upon recommendation of Prince Bernhard, he acted as Inspector General of the Royal Army. In 1953 after promotion to brigadier general he became vice-head and then head of the Royal Military House, where he was responsible for the organization of ceremonies involving the Dutch Royal Family until his retirement in December 1961. During his late years de Mortanges suffered from rheumatism and became eventually confined to a wheelchair. He died in 1971 at the Leiden University Hospital.
Family
On 16 December 1920 de Mortanges married Irma Clara baroness Snouckaert van Schauburg. They had one son, who was executed by the German military after a failed attempt to cross the Franco-Swiss border in 1942. After a divorce on 4 July 1949, on 23 July 1949 de Mortanges married Theresia Gijsbertha Bernardina Daamen.
