Summa Theologica, Part I (Prima Pars) From the Complete...

On the contrary, Strabus, commenting on the text "In the beginning God created heaven and earth," says: "By heaven he does not mean the visible firmament, but the empyrean, that is, the fiery or intellectual firmament, which is not so styled from its heat, but from its splendor; and which was filled with angels directly it was made."

I answer that, As was observed (A. 3), the universe is made up of corporeal and spiritual creatures. Consequently spiritual creatures were so created as to bear some relationship to the corporeal creature, and to rule over every corporeal creature. Hence it was fitting for the angels to be created in the highest corporeal place, as presiding over all corporeal nature; whether it be styled the empyrean heaven, or whatever else it be called. So Isidore says that the highest heaven is the heaven of the angels, explaining the passage of Deut. 10:14: "Behold heaven is the Lord's thy God, and the heaven of heaven."

Reply Obj. 1: The angels were created in a corporeal place, not as if depending upon a body either as to their existence or as to their being made; because God could have created them before all corporeal creation, as many holy Doctors hold. They were made in a corporeal place in order to show their relationship to corporeal nature, and that they are by their power in touch with bodies.

Reply Obj. 2: By the uppermost atmosphere Augustine possibly means the highest part of heaven, to which the atmosphere has a kind of affinity owing to its subtlety and transparency. Or else he is not speaking of all the angels; but only of such as sinned, who, in the opinion of some, belonged to the inferior orders. But there is nothing to hinder us from saying that the higher angels, as having an exalted and universal power over all corporeal things, were created in the highest place of the corporeal creature; while the other angels, as having more restricted powers, were created among the inferior bodies.

Reply Obj. 3: Isaias is not speaking there of any corporeal heaven, but of the heaven of the Blessed Trinity; unto which the sinning angel wished to ascend, when he desired to be equal in some manner to God, as will appear later on (Q. 63, A. 3). _______________________