Wilhelm Bousset Kyrios Christos [1920], p.137; Link, HathiTrust page, forgive my quick and dirty DeepL trans.
Attis is the creative divine elemental force, which drives into matter. If he crosses the Milky Way against the consecration of the mother of the gods and enters the cave of the nymph to marry with her, this means the sinking of the divine elemental force into the lower world. Through the emasculation imposed on him, the mother of the gods brings to a standstill the power that is straying in the unbridled urge to create and calls it back to the heavenly home.
In the midst of these fantasies a strange figure of Oriental origin appears: namely the Primeval Man (Anthropos) sinking into matter and freeing himself from it again. Behind it stands an old myth of the slaughtered (and resurrected) Primeval Man, still not sufficiently illuminated in its meaning as well as in its history. In the Hellenistic syncretistic field it has become a greatness of speculation, a cosmogonic potency.
This figure of the Anthropos appears most clearly and purely in the first treatise of the Hermetic collection {CH 1}. Anthropos, favorite child of the god Nous, breaks through the lower spheres of the Demiurge in his desire to create. Leaning out, he looks at the Physis, which smiles blissfully at him in all its beauty, pulled down by the desire to love, he is embraced and held by the Physis. Here the myth breaks off, its end, the narrative of the liberation of Primeval Man from matter and his elevation into the heavenly Cosmos can easily be completed from the second paraenetic half of the treatise. Then in believers only that takes place, what happened in the destiny of Anthropos.
In most of the Christian-Gnostic systems the myth of the Anthropos has already become an incomprehensible fragment. On the other hand, in the Naassene Sermon (perhaps already in its Hellenistic basis, untouched by Christian influence), it is merged with the figures of Attis, Adonis, Osiris and related gods to the already discussed one great figure of the Dying and Resurrecting God, of the god sinking into matter and rising again. Thus, his figure appears right at the beginning, here in a broad execution, and has pushed the figure of Attis, who obviously played the main role in the cult legend and in the original commentary, into the background,. It thus represents the progressive orientalization process of the syncretistic Hellenistic literature. This is the myth of the dying and suffering god or of Divine Power which sinks into the world of matter and rises again from it.
However, as we have already seen in part, everywhere it takes an anthropological and practically parenetic turn. The god with his Fate in dying and succumbing becomes the type for the fate of the pious, what takes place here is not a unique fact of the past, it "reigns again and again." If we look more closely, just those speculations of the dying and rising god and his cosmic meaning have grown out of the cult and experiences of its believers. Already in this god's cult of dying and to new life awakening this peculiar unio mystica of the faithful with the god is in the offing. This is the obvious meaning of the cult celebration of all dying and resurrecting vegetation deities, that cult participants in mad mourning and exuberant joy take an active and re-living part in the destiny of the god - these connections have also remained in the consciousness of a later time.
In the midst of these fantasies a strange figure of Oriental origin appears: namely the Primeval Man (Anthropos) sinking into matter and freeing himself from it again. Behind it stands an old myth of the slaughtered (and resurrected) Primeval Man, still not sufficiently illuminated in its meaning as well as in its history. In the Hellenistic syncretistic field it has become a greatness of speculation, a cosmogonic potency.
This figure of the Anthropos appears most clearly and purely in the first treatise of the Hermetic collection {CH 1}. Anthropos, favorite child of the god Nous, breaks through the lower spheres of the Demiurge in his desire to create. Leaning out, he looks at the Physis, which smiles blissfully at him in all its beauty, pulled down by the desire to love, he is embraced and held by the Physis. Here the myth breaks off, its end, the narrative of the liberation of Primeval Man from matter and his elevation into the heavenly Cosmos can easily be completed from the second paraenetic half of the treatise. Then in believers only that takes place, what happened in the destiny of Anthropos.
In most of the Christian-Gnostic systems the myth of the Anthropos has already become an incomprehensible fragment. On the other hand, in the Naassene Sermon (perhaps already in its Hellenistic basis, untouched by Christian influence), it is merged with the figures of Attis, Adonis, Osiris and related gods to the already discussed one great figure of the Dying and Resurrecting God, of the god sinking into matter and rising again. Thus, his figure appears right at the beginning, here in a broad execution, and has pushed the figure of Attis, who obviously played the main role in the cult legend and in the original commentary, into the background,. It thus represents the progressive orientalization process of the syncretistic Hellenistic literature. This is the myth of the dying and suffering god or of Divine Power which sinks into the world of matter and rises again from it.
However, as we have already seen in part, everywhere it takes an anthropological and practically parenetic turn. The god with his Fate in dying and succumbing becomes the type for the fate of the pious, what takes place here is not a unique fact of the past, it "reigns again and again." If we look more closely, just those speculations of the dying and rising god and his cosmic meaning have grown out of the cult and experiences of its believers. Already in this god's cult of dying and to new life awakening this peculiar unio mystica of the faithful with the god is in the offing. This is the obvious meaning of the cult celebration of all dying and resurrecting vegetation deities, that cult participants in mad mourning and exuberant joy take an active and re-living part in the destiny of the god - these connections have also remained in the consciousness of a later time.
Although I suppose the vegetation cult is 'universal' (the cave of death and resurrection, ditto), I would argue that Byblos in Lebanon - with its annual red river phenomenon - is a much stronger candidate for an 'original' locus of this myth. Bloody water, visible miles at sea; very supernatural, surely a very ancient sign to attend and worship. The motif needs not be borrowed from far away - it was vividly apparent every year.
As for the next stage, when Anthropos (Man) becomes the god (something more than just psycho-spiritual healing or imagined 'salvation'), I'm not sure when THAT concept starts or where it first becomes fully elaborated. 'Epistle to the Hebrews' (presumably: Apollos to a congregation of heterodox Alexandrian Jews) introduces the Christos as a NEW teaching, c.55 AD: Christos assumes the mantle of the Logos, Jesus becomes the Logos, a Second Son arrives to supplant Melchizedek/Logos. The Christos must be NEW, and strong hints in Philo Judaeus (viz., the Aletheian Anthropos) would confirm this also. If such a myth were already VERY well-known (viz., ancient), doesn't Apollos' teaching seems odd and disjunctive? I strongly doubt this could have originated in Egypt, if Apollos' Alexandrians (Jews) had accepted then dropped this novel Christos belief. Instead, the Anthropos-Christos development should be foreign, introduced lately: perhaps originating in Asia Minor or Babylonia?
Of course, Reitizenstein and Bousset believed the Redeemer Myth had an Iranian origin (Gayomart), but I have no clear ideas on that (beyond their overstatement of the claim).
Wm. Blake's Anthropos