A body of ecclesiastical rules or laws drawn up and imposed by authority in all matters of faith, morals, and discipline. Such laws stem from the early practice of convening councils of church leaders to settle matters of uncertainty and dispute (cf. Acts 15). The importance of the councils determined the degree of authority attached to the canons-those from the Council of Nicea (325), for example, possessed great significance, and the results of other councils appear to be attached to the Nicean. The African churches held frequent plenary sessions that produced a large collection of canonical material, evidenced by reference in the Council of Chalcedon (451) to the Antiochean canons of 341 (or 330).
The councils were not alone in producing canon law. Their work was supplemented by that of individuals, particularly bishops, men such as Gregory Thaumaturgus,* Basil* of Caesarea, and Amphilochius* of Iconium. There was also the work of anonymous and fictitious authors such as the Apostolic Canons.* Papal letters (Decretals) also gained special authority from as early as the letter of Pope Siricius to Himerius of Tarragona in 385. With the Decretal of Gratian about 1140, scholars have drawn the dividing line between ius antiquum and ius novum: all canons after the Council of Trent (1545-63) are called ius novissimum. Gratian's Decretal was eventually extended into the Corpus Iuris Canonici which became the authoritative law for the Roman Church until 1904, when Pius X called for it to be completely overhauled and codified, the standard text now being the Codex Iuris Canonici issued in 1917. Local canons have also been used in conjunction with the authoritative law providing the basic canonical guide.
See A.G. Cicognani, Canon Law (ET 1934), and R. Metz, What Is Canon Law? (1960).