On the Holy Trinity, and of the Godhead of the Holy Spirit.
To Eustathius1 The greater part of this treatise is found also among the Letters of S. Basil [Ep. 189 (80): Ed. Gaume, Tom iii. p. 401 (276 c.)]. The Benedictine edition of S. Basil notes that in one ms. a marginal note attributes the letter to Gregory. It may be added that those parts which appear to be found only in the mss. of Gregory make the argument considerably clearer than it is if they are excluded, as they are from the Benedictine text of S. Basil..
 ΓΡΗΓΟΡΙΟΥ ΕΠΙΣΚΟΠΟΥ ΝΥΣΣΗΣ ΠΡΟΣ ΕΥΣΤΑΘΙΟΝ ΠΕΡΙ ΤΗΣ ΑΓΙΑΣ ΤΡΙΑΔΟΣ