Medieval theologians tend to give a lot of space to angels in their doctrine of creation. For example, when Peter Lombard examines creation, he gives one section (distinction) to creation, then the next 12 to angels, 5 to Genesis 1, and then a few to humanity.

This fascination with angels seems peculiar to many people, and is sometimes made fun of; but I think it's onto something. Here's one part of an argument why, without any claim to originality or definitiveness.

Angels help you get your basic ontology right for one very simple reason: they are incorporeal creatures. If you do justice to both of those terms, much in the doctrine of creation falls into place.

On the one hand, angels are creatures – as fully and truly creatures as anything. Angels are not divine, or semi-divine. They are not mediating entities between God and humanity. They are creatures, brought into being out of nothing.

On the other hand, though, angels are incorporeal. They are not essentially bodily, but only sometimes so. (They can, as Thomas Aquinas makes clear, assume bodies; but they aren't essentially bodily.)

Now, if that's right (just go with it for the moment), that's a big deal, because it means that the most critical ontological division is NOT between spirit and matter. Because spiritual reality can be just as creaturely as material reality.

Being clear about this stops you sliding into a metaphysic where "God is spirit" means that anything spiritual (or intellectual) is divine. Moreover, angels can also be sinful. So thinking about angels helps ward off "Manichean" views, where spirit is good and matter is bad.

The location of the doctrine of angels at the beginning of the doctrine of creation was a profound insight that, if taken seriously, might resource us for meeting the serious scientific challenges a doctrine of creation faces today.