LATIN TEXT: “...Lactantius in libris suis et maxime in Epistolis ad Demetrianum Spiritus Sancti omnino negat substantiam, et errore Judaico dicit eum vel ad Patrem referri vel Filium et sancticationem utriusque Personae sub ejus nomine demonstrari...” - (HIERON. Ep. Ad Pammach. Et Ocean. Chap. 7. Ep. 84. Vall. 41. Ben. 65. al.)

JEROME (circa 347 to 420 C.E.): “...Lactantius in his writings, and especially in his letters to Demetrian, he altogether denies [Ltn., substantiam] the entity of the Holy Spirit, and by a Jewish error says that he is to be referred either to the Father or the Son, and that the holiness of each person is pointed out under his name...” - (Page 244, The divine rule of faith and practice, Volume 1, By William Goode.)

Not Just Lactantius but "...MANY..." according to Jerome didn't believe the holy spirit was part of a Tri{3}nity:

LATIN TEXT: “...Multi per imperitiam Scripturarum (quod et Firmianus in octavo ad Demetrianum Epistolarum libro facit) asserunt Spiritum Sanctum saepe Patrem saepe Filium nominari. Et quum perspice in Trinitate credamus, tertiam Personam auferentes non substantiam ejus volunt esse, sed nomen...” - (ID. In Ep. Ad Gal. Lib. ii. In Chap. 4. ver. 6. ed. Vall. Ven. Tom. Vii. Col. 450.)

JEROME (circa 347 to 420 C.E.): “...( MANY ) through ignorance of the scriptures assert (as also Firmianus does in the eighth book of his Letters to Demetrian) that the Father and Son are often called the Holy Spirit. And while we ought clearly to believe in a Trinity, ( they ) taking away the third Person imagine it to be ( not ) a hypostasis of the Trinity but a name...” - (Page 244, The divine rule of faith and practice, Volume 1, By William Goode.)

Note the dressing down and derogatory smear of "ignorance of the scriptures" - which is far to often - typical of Tri{3}nitarian hard-liners, both old and new.

But of course there is no where at all that the scriptures clearly and straight forwardly, without any mistake call the holy spirit "...GOD..."