Nicene and Post-Nicene Fathers, Ser. II, Vol. VI: The Letters of St. Jerome.: Letter LXXIII
Evangelus had sent Jerome an anonymous treatise in which Melchisedek was identified with the Holy Ghost, and had asked him what he thought of the theory. Jerome in his reply repudiates the idea as absurd and insists that Melchisedek was a real man, possibly, as the Jews said, Shem the eldest son of Noah. The date of the letter is 398 a.d.