But although all the angels are doubtless most happy, and wonderfully resplendent with the glory of every divine gift, yet those are called " Seraphim" who burn with the flames of love: the others "Cherubim" who shine with the splendour of knowledge: those are named " Thrones" who enjoy an inexpressible tranquillity in the divine contemplation: those "Dominations" who rule this lower world, as the ministers of a mighty commander: others "Powers," because they do signs and wonders by the command of their Almighty Lord: others " Principalities," because they have power over the kings and princes of the world: some again are named "Archangels," because they assist the prelates of the Church: and many, in fine, are called " Angels," since they are the guardians and protectors of all that live upon the earth.
--St. Robert Bellarmine,
Eternal Happiness of the Saints
