19 But when they actually found that the communion of the whole world with Cæcilianus continued as before, and that letters of communion from churches beyond the sea were sent to him, and not to the man whom they had flagitiously ordained, they became ashamed of being always silent; for it might be objected to them: Why did they suffer the Church in so many countries to go on in ignorance, communicating with men that were condemned; and especially why did they cut themselves off from communion with the whole world, against which they had no charge to make, by their bearing in silence the exclusion from that communion of the bishop whom they had ordained in Carthage? They chose, therefore, as it is reported, to bring their dispute with Cæcilianus before the foreign churches, in order to secure one of two things, either of which they were prepared to accept: if, on the one hand, by any amount of craft, they succeeded in making good the false accusation, they would abundantly satisfy their lust of revenge; if, however, they failed, they might remain as stubborn as before, but would now have, as it were, some excuse for it, in alleging that they had suffered at the hands of an unjust tribunal—the common outcry of all worthless litigants, though they have been defeated by the clearest light of truth—as if it might not have been said, and most justly said, to them: “Well, let us suppose that those bishops who decided the case at Rome were not good judges; there still remained a plenary Council of the universal Church, in which these judges themselves might be put on their defence; so that, if they were convicted of mistake, their decisions might be reversed.” Whether they have done this or not, let them prove: for we easily prove that it was not done, by the fact that the whole world does not communicate with them; or if it was done, they were defeated there also, of which their state of separation from the Church is a proof.
20. What they actually did afterwards, however, is sufficiently shown in the letter of the Emperor. For it was not before other bishops, but at the bar of the Emperor, that they dared to bring the charge of wrong judgment against ecclesiastical judges of so high authority as the bishops by whose sentence the innocence of Cæcilianus and their own guilt had been declared. He granted them the second trial at Aries, before other bishops; not because this was due to them, but only as a concession to their stubbornness, and from a desire by all means to restrain so great effrontery. For this Christian Emperor did not presume so to grant their unruly and groundless complaints as to make himself the judge of the decision pronounced by the bishops who had sat at Rome; but he appointed, as I have said, other bishops, from whom, however, they preferred again to appeal to the Emperor himself; and you have heard the terms in which he disapproved of this. Would that even then they had desisted from their most insane contentions, and had yielded at last to the truth, as he yielded to them when (intending afterwards to apologize for this course to the reverend prelates) he consented to try their case after the bishops, on condition that, if they did not submit to his decision, for which they had themselves appealed, they should thenceforward be silent! For he ordered that both parties should meet him at Rome to argue the case. When Cæcilianus, for some reason, failed to compear there, he, at their request, ordered all to follow him to Milan. Then some of their party began to withdraw, perhaps offended that Constantine did not follow their example, and condemn Cæcilianus in his absence at once and summarily. When the prudent Emperor was aware of this, he compelled the rest to come to Milan in charge of his guards. Cæcilianus having come there, he brought him forward in person, as he has written; and having examined the matter with the diligence, caution, and prudence which his letters on the subject indicate, he pronounced Cæcilianus perfectly innocent, and them most criminal.
Source: Letters (New Advent)