Letter 492: Theodore Studite, Letter 492; Greek heading: Ἰωάννῃ Γραμματικῷ.

Your Honor has shown the unfeigned character of your sincere love in the corrective notes you made upon the treatise composed by us who are unlearned. And those matters may indeed be reckoned together with the treatise in this way or in that. But since you were at a loss as to how the term "subject" [hypokeimenon, the underlying thing] was understood by us, and how it ought rather to be taken otherwise, as you indicated in your note, we too were at a loss together with you that one wise in all things should be at a loss. For the "subject," O admirable one, according to the blessed Leontius [Leontius of Byzantium, sixth-century theologian], whose scholia are surpassingly excellent, he says to be substance [ousia] together with hypostasis [a concrete, particular existence]. And does not Basil the Great also say, with respect to the Holy Trinity, that there is one in the subject? But indeed the all-wise Dionysius [Dionysius the Areopagite] too says somewhere this: "many in the accidents, one in the subject"; and the accidents are contemplated not in the universal substance, but in the hypostasis, as you know. Therefore, in saying "many in the accidents, one in the subject," he took the "subject" to be substance together with hypostasis; and it is not outside what is fitting, as I think, for it to be set down so in the treatise. For how could that which is not one in the subject be theologized as not being three both in names and in realities, so that the "subject" is nothing other than substance together with hypostasis? But if anything more penetrating should be discovered by Your Holiness, let it not decline to instruct the one who is being praised as a gift by you.