Charles Barbier de la Serre published in 1815 a tactile writing system using raised dots designed to let blind people read and write. In 1821 he presented it at the Royal Institution for Blind Youth in Paris. Louis Braille, a twelve-year-old student, adopted it as a conceptual and technical basis, reduced the cell from twelve to six dots, replaced phonemes with letters, and added musical and mathematical notation. Braille acknowledges his debt to Barbier in his 1829 publication. The Braille system takes the name of its refiner, not its inventor: Barbier remains a footnote while the name of the teenager who improved his idea dominates the history of written accessibility.