On the first day of the Conference, the Donatists challenged the list of the signatures of the Catholic bishops on the document in which they had assigned their representatives. The roll call followed, in which the tribune Marcellinus, who presided, called the Catholic bishops one by one, and their Donatist counterparts were to identify them. Then the roll call proceeded in the opposite way, with the Donatist bishops identified by the Catholics.

The Catholic Bishop Musonius of Zella died shortly before the conference; he was succeded by Donatianus, the last on the list of the Catholic bishops, and acknowledged by the Donatist bishop of the place, Natalicius. However, Maximinus, the Catholic bishop from the neighbourhood, must have ignored this change and the presence of Donatianus, and rushed to affirm the Catholic presence of Zella (as if it was still sede vacante)