6 The second charge, of corresponding with Magnentius.
With regard to the second calumny, that I have written letters to the tyrant (his name I am unwilling to pronounce), I beseech you investigate and try the matter, in whatever way you please, and by whomsoever you may approve of. The extravagance of the charge so confounds me, that I am in utter uncertainty how to act. Believe me, most religious Prince, many times did I weigh the matter in my mind, but was unable to believe that any one could be so mad as to utter such a falsehood. But when this charge was published abroad by the Arians, as well as the former, and they boasted that they had delivered to you a copy of the letter, I was the more amazed, and I used to pass sleepless nights contending against the charge, as if in the presence of my accusers; and suddenly breaking forth into a loud cry, I would immediately fall to my prayers, desiring with groans and tears that I might obtain a favourable hearing from you. And now that by the grace of the Lord, I have obtained such a hearing, I am again at a loss how I shall begin my defence; for as often as I make an attempt to speak, I am prevented by my horror at the deed. In the case of your departed brother, the slanderers had indeed a plausible pretence for what they alleged; because I had been admitted to see him, and he had condescended to write to your brotherly affection concerning me; and he had often sent for me to come to him, and had honoured me when I came. But for the traitor Magnentius, 'the Lord is witness, and His Anointed is witness,' I know him not, nor was ever acquainted with him. What correspondence then could there be between persons so entirely unacquainted with each other? What reason was there to induce me to write to such a man? How could I have commenced my letter, had I written to him? Could I have said, 'You have done well to murder the man who honoured me, whose kindness I shall never forget?' Or, 'I approve of your conduct in destroying our Christian friends, and most faithful brethren.' or, 'I approve of your proceedings in butchering those who so kindly entertained me at Rome; for instance, your departed Aunt Eutropia, whose disposition answered to her name, that worthy man, Abuterius, the most faithful Spirantius, and many other excellent persons?'
Source: Apologia ad Constantium (New Advent)