Charles VII of France ordered his chamberlain to climb Mont Aiguille in 1356. The knight reached the summit of Rocciamelone where he left a bronze triptych of three crosses, a feat which he conducted with the use of ladders to traverse the ice. In 1492 Antoine de Ville climbed Mont Aiguille, without reaching the summit, an experience he described as "horrifying and terrifying." Leonardo da Vinci was fascinated by variations of light in the higher altitudes, and climbed a mountain—scholars are uncertain which one; some believe it may have been Monte Rosa. From his description of a "blue like that of a gentian" sky it is thought that he reached a significantly high altitude. In the 18th century four Chamonix man almost made the summit of Mont Blanc but were overcome by altitude sickness and snowblindness.