The premodern conception of the universe was an amalgam of inherited Greek astronomy (the “Ptolemaic system”), the Bible, philosophical metaphysics (particularly Aristotle), mystical theology/angelology (Pseudo-Dionysius, mediated through Thomas Aquinas), and scholastic speculation. By the High Middle Ages, these traditions had been woven together into an elegant, even sublime model. In this pre-Copernican cosmos, the Earth lay at the center. Deep inside that, underground, was Hell—while above it were nine concentric crystalline spheres, encasing the globe like a Russian doll. Along their circumferences the wandering planets would glide, making an unheard, celestial music. Higher still, above these, was the solid Firmament, studded with fixed, unmoving stars. And beyond this, beyond the Primum Mobile (the “prime mover” of matter)—in fact, beyond all space—lay the Empyrean, the transcendent dwelling-place of the saints, angels, and God in Heaven. It, too, was arranged in concentric circles: a nine-tiered hierarchy of angels, whose holiness increased the nearer they approached the center. For there God was, cloaked in blinding light, and radiating love, wisdom, and blessing in an unbroken chain of being.

The highest articulation of this cosmic schema is to be found in Dante’s Divine Comedy. In that epic, the poet himself traverses this vast hierarchy of being, from Hell all the way up to the Empyrean of Heaven. This latter “place” he describes vividly, connecting the angelology of Pseudo-Dionysius with the Ptolemaic Crystal Spheres by assigning each angelic Hierarchy to a corresponding Sphere. The Empyrean itself, though, is beyond all time and space. Dante envisions it as the “sempiternal rose,” mixing the schema of concentric circles with the image of a rose’s interfolding petals:

Dante gives a canto-long description of the angelic hierarchy/the Empyrean in Paradiso, Canto 28. It is worth quoting at length:

And as I turned around, and my eyes were touched

By that which is apparent in that volume

Whenever on its gyre we intently gaze,

I saw a Point, that was raying out

Light so acute that the sight which it enkindles

Must close before such great intensity.

And whatever star seems smallest here

Would seem to be a moon if placed beside it,

As one star with another star is placed.

…And this was by another circumscribed,

That by a third, the third then by a fourth,

By a fifth the fourth, and then by a sixth the fifth;

The seventh followed hereupon in width,

So ample now, that Juno’s messenger