The theology of the speech has been a subject of perennial dispute among historians, who believe that it has some relevance to the speech’s purpose, date, and authorship. I hope I have shown elsewhere that this is not the case, that the speaker takes no sides in any ecclesiastical quarrel, and that no theological statement in the speech should be regarded as too tendentious or extreme for any particular occasion. Only one passage is of any interest for the history of apologetic, and only for three corollaries—that it indicates the provenance of the speaker, that it makes perfunctory use of pagan sources, and that, in the mouth of Constantine, it adumbrates the parallel that he wished to draw between himself and God:
Plato describes as the First God the one who is above being, rightly so doing, and subordinated this one to a second; and distinguished two beings numerically, the perfection of both being one, but the being of the second receiving its subsistence from the first. For he (sc. the first) is the artisan and governor, being clearly above the universe, while the other, in obedience to his mandates, brings back to him the cause of the constitution of the universe. Thus, according to the accurate account, there would be one God who takes care of all things, having by his Word (logos) put all in order; but the Word himself is God and the child of God. (Oration, 9, p. 163, 18—31 Heikel)
It was the custom of Eastern Christians in this period to affirm a triad (trias) of ‘hypostases’, namely, Father, Son, and Spirit. Some described all three as ‘God’, and some believed, like Arius, that the Father alone is truly God, while the other two have similar attributes by derivation. The conflict between these views persisted even after the Council of Nicaea in 325, when, under the auspices of Constantine as the Eastern sovereign, Arius and his doctrines were condemned. The apologists of the second century tended to ignore the Holy Spirit, and taught that Christ was the emanation and expression of the Father, as a word is the expression of one’s thought. By the time of Constantine, however, such beliefs were out of fashion, and the term logos, if applied to Christ at all, denoted his relation, not to the Father, but to the world. In the West, by contrast, there was little change in doctrine between Tertullian and Lactantius. The latter still ignores the Holy Spirit, and treats the Son as the instrument of the Father’s mediation: ‘God himself, the artisan and founder of all, before he set to work on this brilliant work, the world, brought forth a holy and incorruptible spirit, which he called his Son’ (Divine Institutes, 4. 6. 1).
The conventions of apologetic writing are observed in the Oration by its allusions to philosophy, which, unusually for an author of this period, are cursory, vague, and wholly second hand. A Greek would have been aware that neither Plato nor his followers had used the term logos to designate the hegemonic principle in nature; a professional Latin writer would at least have named a dialogue or attempted a quotation. In the light of modern scholarship, the most probable explanation of our author’s infelicity is that, being a busy amateur, he had read the Latin commentary on the Timaeus by Chalcidius, but mistook it for its source.
Constantine, however, made no mistake in dwelling on the undivided sovereignty of the Father. In later times the implied subordination of the Son could have smelt of heresy (though not strongly); but in the time of Constantine it was orthodox enough, and in any case, granting him to have been the author, there is more than theological meaning in it. From 313 to 324, he shared the Roman government reluctantly with his Eastern colleague Licinius, and I shall argue that the unity of kingship is a leading theme of the speech because the author was aspiring to sole possession of the empire. This theory accounts for another peculiarity: that, unlike the rhetoricians of the Latin Church, he evinces no hostility to the capital, but turns his whole discourse into an encomium on the Christian Church in Rome.