A publication or announcement of the pope, proceeding directly from him, or as is more frequently the case in modern times, issued by papal officials to whom such authority has been delegated. The first example apart from the Epistles of Saint Peter is that of Pope Clement I. Their use increased in proportion with the development of papal primacy, and questions of faith or morals were subjects for letters, variously known with reference to their legal character, as decreta, statuta, decretalia constituta. More general letters, especially those of dogmatic importance, were called tomi, indiculi, commonitoria, epistolae tractoriae, etc. They were early incorporated in collections of canon law and ranked with canons of synods in importance and obligation. The early popes insisted that rescripts issued for individual cases should be observed in analogous ones, an example followed by the popes of the Middle Ages, a period during which the number of papal letters increased enormously. According to the canonists, Gratian in particular, every papal letter of general character was authoritative for the entire Church. The names of letters of general character were varied, e.g., constitution, decree, or decretal; ordinances issued for individual cases were known as rescripta, responsa, or mandata. Instances of forged papal letters were frequent in this period. From the 13th century to 1909 a papal document was given legal form by posting it on the doors of Saint Peter’s, the Lateran, or the Apostolic Chancery, and in the Piazza del Campo di Fiori. Since 1909 they acquire force by publication in the “Acta Apostolicae Sedis.” Modern papal writings are divided into Constitutions, Rescripts, Bulls, Briefs, and Apostolic Letters. The letters are deposited in the Roman archives. Private and official collections of papal letters exist.