Eugène Freyssinet once said, "I left l’X exactly as I entered it, a pure savage dominated by [my] instincts and intuitions." A descendant of craftsmen from Corrèze, who experienced extremely difficult living conditions, Freyssinet upheld a moral duty of promoting low-cost construction without wasting materials or labor. He made his mark on history by inventing prestressed concrete, through the use of pretensioning and adherent wires. This bridge engineer also developed thermal treatment of concrete, flat jacks, and prestressing through use of hydraulic tensioning cylinders and shrink-fitted concrete anchor cones. He created the Technical Society for the Use of Prestressing (Société Technique pour l’Utilisation de la Précontrainte (STUP)) in 1943, which later became a subsidiary of the Vinci company.