Canon, term of ecclesiastical History , signifies a rule or decision, either on dogma or on discipline.

The words is originally Greek, Κανὼν , rule, discipline.

We had the canons of the apostles, the authenticity of which not everyone aggress on, although it is generally admitted that they are very ancient, and various collections of canons of councils, which we indicate, following M. Fleury in his Institution au droit ecclesiastique .

Under the reign of Constantine in 314 were held the Councils of Ancyra in Galatia and Neo-Caesaria in Pontus, which are the oldest from which canons remain to us; then in 325 the general Council of Nicea was held, the canons of which were also gathered. Then there were three particular councils whose canons found great authority: one in Antioch, capital of the Orient, in 341; the other in Laodicea in Phyrgia, around 370; and the third in Gangres in Paphlagonia around 375a finally in 381 a Second universal Council was held in Constantinople.

The canons of these seven councils were gathered into a corpus called the codes of the canons of the Universal Church , to which are added those of the Council of Ephesus, the third ecumenical one held in 430, and those of the Chalcedonian Council, held in 450; to which were added the canons of the apostles , numbering fifty, and those of the Council of Sardique, held in 347, and what is regarded in several churches as a follow-up to the Council of Nicea.

All these canons had been written in Greek, and the churches of the West had an ancient Latin version whose author is not known. The Roman Church used them until the beginning of the 5 ^th century, and the other churches, particularly those of Gaul and Germany, did not agree with the others until the 9 ^th century. But around 530, Abbot Denyis le Petit made another more faithful version of the canons and added all that was in the Greek codex, to wit, the fifty canons of the Apostles, those of the Council of Chalcedonia, and Sardique, of a council of Carthage, and some other African councils. He also made a collection of several papal decrees from Sirice who died in 398 up to Anastasio II, who died in 498. See Decretales.

The collection of Denys le Petit was of such great authority that the Roman Church has since then always used it and called it simply the corpus of canons of the African Church , formed principally of councils held in the time of St. Augustine. The Greeks translated it for their use and Charlemagne, having received it in 787 from Pope Adrian I, brought it to the Gauls.

The Orientals also added canons to the ancient code, that is, the thirty-five canons of the apostles , so that it included 95: the code of the African Church translated into Greek; the canons of the council in trullo , made in 692, to supplement the 5 ^th and 6 ^th councils that had not made canons; those of the Second Council of Nicea, which was the seventh ecumenical one held in 787 – all that comprised the codes of canons of the Church of the East; and these few laws sufficed for 800 years for the whole Catholic Church.

At the end of Charlemagne’s reign, in the West there was spread canons that had been brought from Spain and that bear the name of one Isidore, whom some have nicknamed the merchant , Isidorus mercator ; it contains the eastern canons from a version older than that of Denys le Petit, several canons from the councils of Gaul and Spain, and a great number of popes’ decretals from the first four centuries until Siricius, many of whom were false and pretenders.

Several new compilations of ancient canons have been made, like that of Réginon, Abbot of Prum, who lived in the year 900; that of Burchard, bishop of Vormes, made in the year 1020; that of Yves de Chartres, who lived in 1100; and finally Gratien, the Benedictin of Bologna in Italy, made his around 1151; this is the one most cited in the Canon Law . Fleury, Institution au droit ecclésiastique. Vol. 1, part 1, chapter 1, page 2, 3, 4, 5, 6, 7, 8, and 10.

Gratien put into his collection of texts of the Bible the sentiments of the Fathers on the most important ecclesiastical matters, and titled his book The Concordance of Discordant Danons ; he divided it in order of subjects and not in order of terms, as had been done previously. This compilation is part of the Canonic Law, and is called Decree . See Decree and Canonic.

Since then we have been given various collections of councils that conserve the canons , like that of Fathers Labbe and Cossart, Hardouin, etc.

The canons of the councils are ordinarily conceived in the form of laws, in imperative terms, sometimes conditional, where the injunction is almost always accompanied by the punishment inflicted on those who violate it; when it is a matter of dogma, the canons are sometimes conceived in the form of anathema, which is to say that the Fathers of the Council said an anathema or excommunicated whoever supported one error or another that they had condemned.