Proclus, Theologia Platonica; Michael Psellos

...Intellect being entirely transcendent, and [the Principle] being incorporeal and ineffable; from which all things, even the lowest of beings, necessarily have their subsistence. For not all things are by nature capable of participating in Soul, but only such as have been allotted a life more distinct or more obscure; and it is not possible for those things which are nowhere [living] to enjoy all things, even of Being. But it [the Principle] itself also subsists [as] form; wherefore also the principle of all things is participated by all beings, so far as to be absent from nothing, being the cause of all things that are said to subsist in any way whatever.

And having discovered this first and most ancient principle of the whole, hidden by nature in inaccessible depths; and asserting that even before these, and before bodies, there are monads—I mean first the generic soul—and the supra-intellectual union, it [the science] is accustomed to receive the proper [principles] of the monads: the one intellectual, the other intellectual, the other psychic; for every monad leads a multitude coordinate with itself. And just as it joins incorporeal things to souls, so indeed it joins souls to the intellectual forms, and these to the henads of beings. For all things yet turn back and ascend to the one from above; and having run up as far as this, it considers that it possesses the highest limit of the contemplation of the whole.

And [it says] that this is the most holy [science] concerning the gods, which treats of the henads of beings, and their processions and their idioms in relation to one another, and the connection of beings to them, and the orders [derived] from them, which depend upon these eternal hypostases. But the contemplation which treats of Intellect and the forms and the genera of Intellect is second to the science that treats of the gods themselves. And it says that while the soul is able to grasp this [second science] a little and to know it through intuition, that [science] which transcends it is of ineffable and unspeakable existences; for after the [intellectual] order, he who is strictly silent regarding them [obtains] the manifestation from a single cause. Whence I think that the intellectual characteristic of the soul is capable of apprehending the intellectual forms and the difference within them; but the summit of the intellect and as—

Soul. Intellect.
The Good. Beyond
intellect. Psychic.
Intellectual. God
is the henad.

The
flower of the intellect.