In the strictest sense of the word, "decretal" means a papal rescript (rescriptum), an answer of the pope when he has been appealed to or his advice has been sought on a matter of discipline. The oldest preserved decretal is a letter of Pope Siricius in response to an inquiry from Himerius, Bishop of Tarragona, in which Siricius issued decisions on fifteen different points, on matters regarding baptism, penance, church discipline and the celibacy of the clergy.Kirsch, Johann Peter. "Pope St. Siricius." The Catholic Encyclopedia Vol. 14. New York: Robert Appleton Company, 1912
