Angels & the Celestial Hierarchy

Angels — created spiritual beings who serve as God's messengers, guard the faithful, and worship around the throne — pervade scripture and the whole Christian imagination. Their existence is affirmed by every tradition. Their detailed ordering into nine ranks or “choirs” (seraphim, cherubim, thrones, and so on) was given its classic form by the early-sixth-century author known as Pseudo-Dionysius the Areopagite in The Celestial Hierarchy, and elaborated by Thomas Aquinas. This speculative angelic taxonomy is especially developed in Catholic and Orthodox thought, while the basic doctrine of angels is shared across the Church.