Personification of day
|Parents||Chaos and Caligine|
|Siblings||Nox, Erebus, and Aether|
|Children||Terra, Caelus, Mare|
According to the Roman mythographer Hyginus, Chaos and Caligine were the parents of Nox (Night), Dies, Erebus (Darkness), and Aether. Cicero says that Aether and Dies were the parents of Caelus (Sky). While, Hyginus says that, in addition to Caelus, Aether and Dies were also the parents of Terra (Earth), and Mare (Sea). Cicero also says that Dies and Caelus were the parents of Mercury, the Roman counterpart of Hermes.
The Latin noun diēs is based on the Proto-Italic accusative singular *dijēm, itself stemming from the Proto-Indo-European root *dyeu-, denoting the "diurnal sky" or the "brightness of the day" (in contrast to the darkness of the night). The corresponding Proto-Indo-European day god is Dyeus.