IV. Even the authors of the mischief may find room for forgiveness by repentance.
If, therefore, your clemency deigns to reflect upon my motives, it will be satisfied that I have acted throughout with the design of bringing about the abolition of the heresy without the loss of one soul; and that in the case of the authors of these cruel disturbances I have modified my practice somewhat in order that their slow minds might be aroused by some feelings of compunction to ask for lenient treatment. For although since their decision, which is no less blasphemous than unjust, they cannot be held in such honour by the Catholic brotherhood as they once were, yet they still retain their sees and their rank as bishops, with the prospect either of receiving the peace of the whole Church, after true and necessary signs of repentance or, if (which God forbid) they persist in their heresy, of reaping the reward of their misbelief. Dated 20th of July, in the consulship of the illustrious Adelfius (451).
Source: Letters (New Advent)