Irenaeus (Against Heresies, c. 180 CE) reports Basilides teaching a ruler named Abraxas whose Greek letter values sum to 365, matching the heavens' daily powers. Hundreds of engraved gems show the hybrid figure with shield and whip, called Abrasax in the inscriptions. Whether the gems depict Basilides' god is disputed.
Jung's Septem Sermones ad Mortuos (1916, privately printed) made Abraxas the god beyond God and devil, the union of opposites, launching his modern esoteric career from occult paperback to Hermann Hesse's Demian. Most people who invoke Abraxas today are quoting Jung, not Basilides.
The functional reading of the gems: 365 as a completeness charm, the whole year bound into a name, protection by calendar. Abraxas may be less a deity than a spell that learned to stand upright, arithmetic wearing a body.
Is Abraxas a god, a word, a number, or a mirror held up to whoever names him?