"The anonymous text that is usually called the Prayer of Saint Francis is often associated with the Italian Saint Francis of Assisi (c. 1182 – 1226), but entirely absent from his writings. The prayer in its present form has not been traced back further than 1912. Its first known occurrence was in French, in a small spiritual magazine called La Clochette (The Little Bell), published by a Catholic Church organization in Paris named La Ligue de la Sainte-Messe (The League of the Holy Mass). The author's name was not given, although it may have been the founder of La Ligue, Father Esther Bouquerel."
slightly paraphrased from wikipedia