Bernard of Clairvaux; but the fact that it contains a quotation from St. Francis of Assisi, who was born thirty years after the death of St. Bernard, disposes of this theory. In England there exist many manuscripts of the first three books, called “Musica Ecclesiastica,” frequently ascribed to the English mystic Walter Hilton. But Hilton seems to have died in 1395, and there is no evidence of the existence of the work before 1400