Canon XCIX. (Greek ciii.)
Of people or dioceses returned from the Donatists.
Such communities as have returned from the Donatists and have had bishops, without doubt may continue to have them even without any action of the councils, but such a community as had a bishop and when he dies wish no longer to have a bishop of their own, but to belong to the diocese of some other bishop, this is not to be denied them. Also such bishops as before the promulgation of the imperial law concerning unity as brought back their people to the Catholic Church, they ought to be allowed still to rule them: but from the time of that law of unity, all the Churches, and their dioceses, and if perchance there be any instruments of the Church or things pertaining to its rights should belong to the Catholic bishops of those places to whom the places pertained while under the heretics, whether they be converted to the Catholic Church or remain unconverted heretics. Whoever after this law shall make any such usurpation, shall restore as is meet the usurped possessions.
p. 493 Notes.
Ancient Epitome of Canon XCIX.
Whoever are converted from the Donatists may retain their own bishops, although they had them without the consent of the synod; and when the bishop is dead, if they do not wish another to be substituted in his room, but desire to place themselves under some other bishop, they shall be allowed to do so. And such bishops as before the union have brought back the people they ruled, let them still rule them. After the imperial Edict on Unity every church must defend its own rights.
This canon is Canon v. of Carthage, a.d. 407.
“An imperial law concerning unity” i.e. For uniting all in the catholic faith, and ejecting the donatistical bishops.