Translated by Cardinal Newman.
Introduction to the Apologia Ad Constantium.
This address to the Emperor in defence against certain serious charges (see below) was completed about the time of the intrusion of George, who arrived at Alexandria on Feb. 24, 357. The main, or apologetic, part of the letter was probably composed before George's actual arrival, in fact at about the same date as the encyclical letter which immediately precedes; S:S:27 and following (see 27, note 2) forming an added expostulation upon hearing of the general expulsion of Catholic Bishops, and of the outrages  at Alexandria. It is quite uncertain whether it ever reached the emperor; whether it did so or not, his attitude toward Athanasius was in no way affected by it. It had probably been begun with the idea of its being actually delivered in the presence of Constantius (see S:S:3, 6, 8, 16 'I see you smile,' 22), but, although by a rhetorical fiction the form of an oral defence is kept up to the end, the concluding sections (27, 32 init.) shew that any such idea had been renounced before the Apology was completed. The first 26 sections are directed to the refutation of four personal charges, quite different from those of the earlier period, rebutted in the Apology against the Arians. They were (1) that Athanasius had poisoned the mind of Constans against his brother (2-5). To this Ath. replies that he had never spoken to the deceased Augustus except in the presence of witnesses, and that the history of his own movements when in the West entirely precluded any such possibility. The third and fourth sections thus incidentally supply important details for the life of Athanasius. (2) That he had written letters to the 'tyrant' Magnentius (6-13), a charge absurd in itself, and only to be borne out by forgery, but also amply disproved by his known affection toward Constans, the victim of the 'tyrant.' (3) That he had (14-18) used the new church in the 'Caesareum,' before it was completed or dedicated, for the Easter festival of 355 (Tillem. viii. 149).
 See Apol. Fug. 6, note 5.
Reference address : https://www.elpenor.org/athanasius/defence-constantius.asp