(Found translated in Lib. cit., p. 212 et seqq. Epistle clx.)
Contains the preface of his letter to Diodorus Bishop of Tarsus, in which he tells him of a letter shewed him in justification of a man's marrying two sisters bearing his name; but he hopes it was forged.
Contains the rest of the letter, in which he argues and inveighs against this practice.