Pseudo-Dionysius (On the Celestial Hierarchy) and Saint Thomas Aquinas (Summa Theologiae) drew on passages from the New Testament, specifically Ephesians  and Colossians 1:16, to develop a schema of three Hierarchies, Spheres or Triads of angels, with each Hierarchy containing three Orders or Choirs.
The theologians Pseudo-Dionysius (On the Celestial Hierarchy) and Saint Thomas Aquinas (Summa Theologiae) utilized biblical passages from Ephesians  and Colossians 1:16 to construct a hierarchical structure of three angelic realms, comprising three orders or choirs within each realm.