Catholic Encyclopedia (1913)/Seal
The use of a seal by men of wealth and position was common before the Christian era. It was natural then that high functionaries of the Church should adopt the habit as soon as they became socially and politically important. An incidental allusion in one of St. Augustine's letters (217 to Victorinus) lets us know that he used a seal. The practice spread and it seems to be taken for granted by Clovis at the very beginning of the Merovingian period (Mon. Germ. Hist.: Leg., II, 2). Later ecclesiastical synods require that letters under the bishop's seal should be given to priests when for some reason they lawfully quitted their own proper diocese. So it was enacted at Chalon-sur-Saône in 813. Pope Nicholas I in the same century complains that the bishops of Dôle and Reims had contra morem sent their letters to him unsealed (Jaffé, "Regesta", nn. 2789, 2806, 2823). The custom of bishops possessing seals may from this date be assumed to have been pretty general. At first they were only used for securing the document from impertinent curiosity and the seal was commonly attached to the ties with which it was fastened. When the letter was opened by the addressee the seal was necessarily broken. Later the seal served as an authentication and was attached to the face of the document. The deed was thus only held to be valid so long as the seal remained intact. It soon came to follow from this point of view that not only real persons like kings and bishops, but also every kind of body corporate, cathedral chapters, municipalities, monasteries, etc., also required a common seal to validate the acts which were executed in their name,
During the early Middle Ages seals of lead, or more properly "bulls", were in common use both in East and West, but except in the case of the papal chancery, these leaden authentications soon went out of favour in western Christendom and it became the universal practice to take the impressions in wax. In England hardly any waxen seals have survived of earlier date than the Norman Conquest. In the British Museum collection the earliest bishop's seals preserved are those of William of St. Carileph, Bishop of Durham (1081-96) and of St. Anselm, Archbishop of Canterbury (1093-1109). The importance of the seal as a means of authentication necessitated that when authority passed into new hands the old seal should be destroyed and a new one made. When the pope dies it is the first duty of the Cardinal Camerlengo to obtain possession of the Fisherman's Ring, the papal signet, and to see that it is broken up. A similar practice prevailed in the Middle Ages and it is often alluded to by historians, as it seems to have been a matter of some ceremony. Thus we are concisely told: "There died in this year Robert de Insula, Bishop of Durham. After his burial, his seal was publicly broken up in the presence of all by Master Robert Avenel." (Hist. Dunel. Scrip. Tres., p. 63). Matthew Paris gives a similar description of the breaking of the seal of William, Abbot of St. Albans, in 1235.
GIRY, Manuel de Diplomatique (Paris, 1894), 622-657; DEMAY, Inventaire des sceaux de la Normandie (Paris, 1881); BIRCH, Seals, Connoisseurs' Library (1907); BIRCH, Catalogue of Seals in British Museum (London, 1887-99); D'ARCQ, Collection de Sceaux (3 vols., Paris, 1868).