Empyrean: In ancient cosmologies, the Empyrean Heaven, or simply the Empyrean, was the place in the highest heaven, which was supposed to be occupied by the element of fire (or aether in Aristotle’s natural philosophy). The word derives from the Medieval Latin empyreus, an adaptation of the Ancient Greek empyros (ἔμπυρος), meaning “in or on the fire (pyr)”
Empyreum (The Divine Comedy, Gustave Doré )
The Empyrean was thus used as a name for the firmament, and in Christian literature for the dwelling-place of God, the blessed, celestial beings so divine they are made of pure light, and the source of light and creation. Notably, at the very end of Dante’s Paradiso, Dante visits God in the Empyrean.