Portions of this letter are found quoted by various ancient Fathers, e.g. by Popes Vigilius and Pelagius II. in the sixth cent; by Facundus, bishop of Hermiæ, in the same century, and almost one half of the whole by Prudentius, bishop of Troyes (ninth cent.) in his famous treatise on Predestination against John Scotus Erigena. Quesnel, however, appears to have been the first to print it as a whole ex codice Grimanico; after which the Ball. also discovered it in the Ratisbon ms.