Pope [St.] Celestine I, in an epistle to John of Antioch, which is contained in Volume One of the Council of Ephesus, ch. 19, says: “If anyone who was either excommunicated or exiled by Bishop Nestorius, or any that followed him, from such a time as he began to preach such things, whether they be from the dignity of a bishop or clergy, it is manifest that he has endured and endures in our communion, nor do we judge him outside, because he could not remove anyone by a sentence, who himself had already shown that he must be removed.” And in a letter to the clergy of Constantinople: “The Authority of our See has sanctioned, that the bishop, cleric or Christian by simple profession who had been deposed or excommunicated by Nestorius or his followers, after the latter began to preach heresy, shall not be considered deposed or excommunicated. For he who had defected from the faith with such preaching, cannot depose or remove anyone whatsoever.” (As quoted by St. Robert Bellarmine, De Romano Pontifice: On the Roman Pontiff, trans. by Ryan Grant [Mediatrix Press, 2015], p. 308)