Lieutenant-Colonel Rollet entering Chateau-Salins, Moselle, France, 17 November 1918. By French photographer C Bergeret. The French Foreign Legion was established in 1831 as an elite unit of foreign volunteers. The Legion's primary function in the 19th and early 20th century was the expansion and protection of France's overseas territories, but it served with distinction in World War I. Known as the 'Father of the Legion', Lieutenant-Colonel Rollet commanded the Legion's Regiment de Marche.