Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Councils of Ancyra, Gangra, Neocæsarea, Antioch and Laodicea, which Canons were Accepted and Received by the Ecumenical Synods.: Canon V

Canon V.

If any presbyter or deacon, despising this own bishop, has separated himself from the Church, and gathered a private assembly, and set up an altar; and if, when summoned by his bishop, he shall refuse to be persuaded and will not obey, even though he summon him a first and a second time, let such an one be wholly deposed and have no further remedy, neither be capable of regaining his rank.  And if he persist in troubling and disturbing the Church, let him be corrected, as a seditious person, by the civil power.

p. 111 Notes.

Ancient Epitome of Canon V.

Any presbyter or deacon who spurns his bishop, and withdraws from him, and sets up another altar, if after being thrice called by the bishop, he shall persist in his arrogancy, let him be deposed and be deprived of all hope of restoration.

It will be noted that the Ancient Epitome mentions three warnings, and the canon only two.  The epitome in this evidently follows the Apostolical Canon, number thirty-one.  It is somewhat curious that Aristenus in commenting on this canon does not note the discrepancy.

Van Espen.

This canon, together with the preceding was read from the Code of Canons at the Council of Chalcedon, at the Fourth Session in connexion with the case of Carosus and Dorothœus, and of other monks who adhered to them.  And a sentence in accordance with them was conceived in these words against those who would not obey the Council in the condemnation of Eutyches, “Let them know that they together with the monks who are with them, are deprived of grade, and of all dignity, and of communion, as well as he, so that they cease to preside over their monasteries:  and if they attempt to escape, this holy and universal great council decrees the same punishment shall attach to them, that is to say the external authority, according to the divine and holy laws of the Fathers, shall carry out the sentence passed against the contumacious.”

This canon shews that monks and clerics who were rebellious were sometimes coerced by the Secular Power, when the ecclesiastical power was not sufficient to coerce them, and hence it was that the secular arm was called in.

Compare with this Apostolic Canon XXXI.

The last clause of this canon is found in the Corpus Juris Canonici, Gratian’s Decretum, Pars II. Causa XI., Quæst VIII. Can. vij.  (The Latin however for “by the civil power” is, as is pointed out by the Roman Correctors, per forinsecam potestatem or per forasticam potestatem.