VI. Donatus, a converted Novatian, and Maximus, an ex-Donatist, are retained in their episcopal office.
Donatus of Salacia, who, as we learn, has been converted from the Novatians with his people, we wish to preside over the Lord's flock, on condition that he remembers he must send a certificate of his faith to us, in which he not only condemns the error of the Novatian dogma, but also unreservedly confesses the Catholic truth. Maximus, also, although he was culpably ordained when a layman, yet if he is now no longer a Donatist, and has abjured the spirit of schismatic depravity, we do not depose from his episcopal dignity, which he has obtained irregularly, on condition that he declare himself a Catholic by drawing up a certificate for us.
Source: Letters (New Advent)