Hebdomad

A characteristic feature of the Gnostic concept of the universe is the role played in almost all Gnostic systems by the seven world-creating archons, known as the Hebdomad.

These Seven are in most systems semi-hostile powers, and are reckoned as the last and lowest emanations of the Godhead; below them and frequently considered as proceeding from them, comes the world of the actually devilish powers.

There are indeed certain exceptions; Basilides taught the existence of a "great archon" called Abraxas who presided over 365 archons.

Evidently from works such as the Apocryphon of John, the Ophite Diagrams, On the Origin of the World and Pistis Sophia, archons play an important role in Gnostic cosmology.

Probably originally referring to the Greek daimons of the planets, in Gnosticism they became the demonic rulers of the material world, each associated with a different celestial sphere.

As rulers over the material world, they are called archontes, "principalities", or "rulers".

As with ancient astronomy, which thought of a sphere of fixed stars, above the spheres of the seven planets, beyond the spheres of the evil archons (Hebdomad), there were the supercelestial regions which a soul must reach by gnosis to escape the dominion of the archons.

This place is thought of as the abode of Sophia (Wisdom) and Barbelo, also called Ogdoad.

https://en.m.wikipedia.org/wiki/Archon_(Gnosticism)