Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Synods of Sardica, Carthage, Constantinople, and Carthage Under St. Cyprian, Which Canons Were Received by the Council in Trullo and Ratified by II. Nice.: Canon LI

Canon LI.  (Greek lv.)

That the date of Easter is to be announced by the Church of Carthage.

Honoratus and Urban, the bishops, said:  Since all things treated by our commonitory are known, 453 we add also what has been ordered concerning the day of Easter, that we be informed of the date always by the Church of Carthage, as has been accustomed and that no short time before.  Aurelius, the bishop, said:  If it seems good to your holiness, since we remember that we pledged ourselves sometime ago that every year we would come together for discussion, when we assemble, then let the date of the holy Easter be announced through the legates present at the Council.  Honoratus and Urban, the bishops, said:  Now we seek of the present assembly that ye deign to inform our province of that day by letters.  Aurelius, the bishop, said:  It is necessary it should be so.

Notes.

Ancient Epitome of Canon LI.

Let the day on which Easter is to be kept be announced by the Church of Carthage in the annual synod.

This canon is the first part of Canon iv. of the Synod of Carthage, August 28th, 397.

Johnson.

The synod met in August.  See Can. 73.

Footnotes

The Latin “noscuntur” is almost certainly corrupt, Van Espen suggests “absoluta sunt” as the meaning.