“Later, in the Pythagorean speculations, Zeus became the metaphysical trinity; the monad evolving from its invisible SELF the active cause, effect, and intelligent will, the whole forming the Tetractis.
Still later we find the earlier Neoplatonists leaving the primal monad aside, on the ground of its utter incomprehensibleness to human intellect, speculating merely on the demiurgic triad of this deity as visible and intelligible in its effects; and thus the metaphysical continuation by Plotinus, Porphyry, Proclus, and other philosophers of this view of Zeus the father, Zeus Poseidon, or dunamis, the son and power, and the spirit or nous.
This triad was also accepted as a whole by the Irenaeic school of the second century; the more substantial difference between the doctrines of the Neo-platonists and the Christians being merely the forcible amalgamation by the latter of the incomprehensible monad with its actualized creative trinity.”
H. P. Blavatsky