The Melitian Schism in Alexandria was essentially over the same issue as the Donatist Controversy which raged in the North African church during the early fourth century, following the persecution by Diocletian. It should not be confused with another controversy also called the Melitian Schism, which occurred in the church in Antioch, later in the fourth century, following the Council of Nicaea.
The persecution of the church by the Emperor Diocletian was the final persecution by the Roman Empire. Following this persecution, the church was again left with the problem of church discipline over what to do with lapsed believers. These were either those who had performed pagan sacrifices to avoid suffering, or those who had paid bribes to obtain certificates (Libellus) declaring they had performed the sacrifices.
Melitius was the bishop of Lycopolis in Egypt, who took a rigorous position over church discipline. He complained that Peter, the bishop of Alexandria, had too lax an attitude towards lapsed believers, in allowing them back into the fellowship of the church. Melitius protested against the position taken by Peter by ordaining some of his own supporters. In response to this, Peter excommunicated Melitius. One of the people involved in the ordinations by Melitius was Arius. For this he was initially suspended from ministry, but was later restored and given charge of the church in the port area of Alexandria.
The Council of Nicaea in 325 attempted to bring the Melitian schism to an end, with the aim of bringing them back into the Catholic Church. However, they were only partially successful. They agreed to allow Melitian clergy to continue their ministry, but their ordination must be re-confirmed by the Catholic Church and they must submit to Alexander, the new bishop of Alexandria. They even allowed Melitius to retain the title of bishop, although he was not given his own see, and was no longer allowed to ordain his own clergy.
During the Arian Controversy, the Melitians supported the condemnation of Athanasius as the council held at Tyre in 335, accusing him of being cruel in his treatment of them. In 362, a council was held in Alexandria, in which Athanasius again attempted to bridge the gap with the Melitians. They had probably taken a ‘semi-Arian’ position in the Arian Controversy, by saying that the Son was of like substance (homoiousia) with the Father, rather than the Nicaean position, which declared that the Son was of one substance (homoousia) with the Father.
The Melitians were never totally brought back into the Catholic Church. Small groups of them continued to exist in monastic communities until the eighth century.