An Historical Summary of Angelic Hierarchies from Part VII: The “Seven” Thrones in In Operibus Sigillo Dei Aemeth by David Richard Jones.

“Although scholarly opinion differs as to its date of composition and origin, the earliest form of this text can be traced to what is now referred to as that Aramaic Levi Document. And though the text of The Testaments of the Twelve Patriarchs is clearly a compilation by an early Christian author (circa 2C C.E.), it is now known with certainty to have been derived from pre-Christian, and probably sectarian Jewish sources.” [via]