 At the museum's Institute of Human Paleontology, he became a friend of Henri Breuil and in 1913 took part with him in excavations at the prehistoric painted Cave of El Castillo in northwest Spain.Mobilized in December 1914, Teilhard served in World War I as a stretcher-bearer in the 8th Moroccan Rifles.For his valor, he received several citations, including the Médaille militaire and the Legion of Honor.