The Peace Prayer of St. Francis is a famous prayer which first appeared around the year 1915 A.D., and which embodies the spirit of
According to Father Kajetan Esser, OFM, the author of the critical edition of St. Francis’s Writings, the Peace Prayer of St. Francis is most certainly not one of the writings of St. Francis. This prayer, according to Father Schulz, Das sogennante Franziskusgebet. Forshungen zur evangelishen Gebetslitteratur (III), in Jahrbuch fur Liturgik und Hymnologie, 13 (1968), pp. 39-53, first appeared during the First World War. It was found written on the observe of a holy card of St. Francis, which was found in a Normal Almanac. The prayer bore no name; but in the English speaking world, on account of this holy card, it came to be called the Peace Prayer of St. Francis.
More information about this prayer can be found in Friar J. Poulenc, OFM, L’inspiration moderne de la priere « Seigneru faites de moi un instrument de votre paix », Archivum Franciscanum Historicum, vol. 68 (1975) pp. 450-453.