Alypius the bishop, a legate of the province of Numidia, said: Nor should this be passed over; if by chance any presbyter when corrected by his bishop, inflamed by self-conceit or pride, has thought fit to offer sacrifices to God separately [from the authority of the bishop] or has believed it right to erect another altar, contrary to ecclesiastical faith and discipline, such should not get off with impunity. Valentine, of the primatial see of the province of Numidia, said: The propositions made by our brother Alypius are of necessity congruous to ecclesiastical discipline and faith; therefore enact what seems good to your belovedness.
Ancient Epitome of Canon X.
If one condemned by his bishop shall separate himself and set up an altar or make the offering he should be punished.
Whoever has been cut off by his own bishop and does not go to the synod to which his bishop is subject, that an examination may be made of the grounds of his cutting off, and that whatever is contrary to justice may be corrected; but, puffed up with pride and conceit, shall despise the synod and separate himself from the Church, and shall set up another altar, and shall offer to God the holy gifts; such an one shall not be allowed to go on with impunity, since he is acting contrary to the faith and constitution of the Church; but he is to be stricken with anathema.
This and the following canon are Canon viii. of the so often mentioned synod of 387 or 390.
See Canon of the Apostles 24 (or 32) and that of Gangra 6.