It was soon clear, by the exclusion of the "Pars Majorini" from certain privileges conferred on the African church, that the sympathies of Constantine were with the other party (Eusebius, _Hist. eccl._ x. 6, 7). To investigate the dispute an imperial commission was issued to five Gallic bishops, under the presidency of Melchiades, bishop of Rome. The number of referees was afterwards increased to twenty, and the case was tried at Rome in 313.[2] Ten bishops appeared on each side, the leading representative of the Donatists being Donatus of Casae Nigrae. The decision was entirely in favour of Caecilian, and Donatus was found guilty of various ecclesiastical offences. An appeal was taken and allowed; but the decision of the synod of Arles in 314 not only confirmed the position of Caecilian, but greatly strengthened it by passing a canon that ordination was not invalid because performed by a traditor, if otherwise regular. Felix had previously been declared innocent after an examination of records and witnesses at Carthage. A further appeal to the emperor in person was heard at Milan in 316, when all points were finally decided in favour of Caecilian, probably on the advice of Hosius, bishop of Cordova. Henceforward the power of the state was directed to the suppression of the defeated party. Persistent Donatists were no longer merely heretics; they were rebels and incurred the confiscation of their church property and the forfeiture of their civil rights.
The attempt to destroy the sect by force had the result of intensifying its fanaticism. Majorinus, the Donatist bishop of Carthage, died in 315, and was succeeded by Donatus, surnamed Magnus, a man of great force of character, under whose influence the schism gained fresh strength from the opposition it encountered. Force was met with force; the Circumcelliones, bands of fugitive slaves and vagrant (_circum cellas_) peasants, attached themselves to the Donatists, and their violence reached such a height as to threaten civil war. In 321 Constantine, seeing probably that he had been wrong in abandoning his usual policy of toleration, sought to retrace his steps by granting the Donatists liberty to act according to their consciences, and declaring that the points in dispute between them and the orthodox should be left to the judgment of God. This wise policy, to which he consistently adhered to the close of his reign, was not followed by his son and successor Constans, who, after repeated attempts to win over the sect by bribes, resorted to persecution. The renewed excesses of the Circumcelliones, among whom were ranged fugitive slaves, debtors and political malcontents of all kinds, had given to the Donatist schism a revolutionary aspect; and its forcible suppression may therefore have seemed to Constans even more necessary for the preservation of the empire than for the vindication of orthodoxy. The power which they had been the first to invoke having thus declared so emphatically and persistently against them, the Donatists revived the old world-alien Christianity of the days of persecution, and repeated Tertullian's question, "What has the emperor to do with the church?" (_Quid est imperatori cum ecclesia?_) Such an attitude aggravated the lawlessness of the Circumcellion adherents of the sect, and their outrages were in turn made the justification for the most rigorous measures against the whole Donatist party indiscriminately. Many of their bishops fell victims to the persecution, and Donatus (Magnus) and several others were banished from their sees.