Just going to share something I wrote today in response to a question on Discord. The question concerned whether Proclus or other late antique Platonists merely invented the doctrine stated by Proclus in his Timaeus commentary that “Each of the Gods is the universe, but after a different manner,” (In Tim. I, 308), that “Each of the Gods is denominated from his peculiarity, though each is comprehensive of all things,” (IT I, 312).

It's too simplistic to say that this doctrine either comes verbatim from Plato himself, or is made up by Proclus. In the first place, it goes back at least as far as Plotinus explicitly, who states that "Each God is all the Gods coming together into one" (Enn. V.8.9.17). But there are indications that it is far older. Speusippus, Plato's immediate successor, taught a form of holism characterized by Aristotle as holding that in order to really know any one thing, one would have to know everything. If this doctrine was not to be deflationary, as the similar doctrine of dependent origination is among Buddhists, then it would demand that there are certain units the identity of which can ground this. And indeed, we find Aristotle criticizing the Platonists for advocating in effect "a profusion of Goods" (Metaph. 1091b25)—not a mere profusion of good things, that is, but a profusion of measures of Goodness. The Good Itself, therefore, was many for them. Let's go back to Plato himself. We may not know exactly how the henology of the Parmenides was interpreted in discussions between Plato and his pupils, but it would hardly be reasonable to think that the direction this doctrine took when it becomes available to us, due to lack of preservation of the texts of Plato's immediate successors, was some arbitrary invention. Note that in the Timaeus, while the paradigm for the demiurge's activity is singular in one respect, Timaeus also states that the cosmos is "a cult statue of the eternal Gods" (Tim. 37c), where note the plural. This shows that the cosmos can indeed for Plato be grounded ultimately in each God, and that the singularity of the paradigm is a one-to-one correspondence of the cosmos with each God. Radical or polycentric polytheism was not something merely invented by Proclus or other late antique Platonists.