Solresol is a constructed language devised by François Sudre, beginning in 1827. His major book on it, Langue musicale universelle, was published after his death in 1866, though he had already been publicizing it for some years. Solresol enjoyed a brief spell of popularity, reaching its pinnacle with Boleslas Gajewski's 1902 posthumous publication of Grammaire du Solresol.