Dyēus or Dyḗus ph₂tḗr is the Proto-Indo-European Sky father, being the personification of the bright sky of the day and the seat of the gods, his wife is Dʰéǵʰōm the mother-earth goddess.
Role[]
King of the Gods[]
Dyēus´ role is presumably to be the king of the gods in the Proto-Indo-European pantheon; this is based on other Indo-European sky fathers like Zeus, Jupiter, Dievas, and Dyaus.
Underworld[]
Although Dyēus is a sky father, ironically some descendants of Dyēus are not sky fathers; the Roman Dīs Pater is an underworld deity similar to the Greco-Roman Pluto rather than Jupiter. Originally the Avestan word dyaoš meant heaven, but later, after Zoroaster's reform, dyaoš became diiaoš, which is used for demons and hell.
In Zoroastrianism, both Daevas and Dews are derived from their own word for Dyēus.
Fall of Dyēus[]
For some Indo-European pantheons, the descendants of Dyēus are not the main god, like Persian mythology, Hindu mythology, Slavic mythology, Norse mythology, and Germanic mythology. This might be so because for these Indo-European cultures the cult of Dyēus was not important or were influenced by other cultures, so their main gods became either Perkʷūnos or Wérunos rather than Dyēus.
A lost myth may exist in which Dyēus lost his role as the king of the gods and was replaced by his son or brother, similar to the Vedic myth of Dyaus and Indra.
Consort/Female Equivalent[]
There is a hypothesis that the consort of Dyēus is not Dʰéǵʰōm but Dyēus' female equivalent *Diwōnā.
This is supported for the names of the goddesses Dione, Devana, and debatably Zisa and Diana come from*Diwōnā.
Legacy[]
Dyēus as a name for a day[]
Both the words Tuesday and Jueves (Thursday in Spanish) have their origins in Dyēus, as Tuesday is derived from Tyr´s day, and Tyr comes from the Proto-Germanic Tiwaz which is originally from Dyēus. Jueves comes from the Latin dies Jovis (Jupiter´s day), and the name Jupiter also has its origin in Proto-Indo-European Dyēus.
Dyēus as a name for the Biblical God[]
Many people who speak Indo-European languages use a word derived from Dyēus to refer to Yahweh; for example, the Baltics use the name of Dievas for the Abrahamic God, and equally, the Christian Albanians use the word Zojz for the Abrahamic God too.
Curiously, the Latin word Deus also has its origin on Dyēus, and also was used for the Latin translation of the of the Bible for the biblical god.
Actually, many words derived from the Latin Deus like Dios, Dio, and many others are used for the Judeo-Christian God.
Miscellaneous[]
The planet Jupiter was named after the Roman god of the same name, Jupiter comes from Iup (Sky) that has its origins on the Proto-Indo-European word *Dyēus and Piter (Father) which comes from the Proto-Indo-European word ph₂tḗr.
The Hindu deities as a whole are called Devas, whose name comes from Dyēus, the word deva is also use in Buddhism and some new age movements.
The goddess Diana also comes from Dyēus via Proto-Indo-European *diwyós (divine) which is a derivative of *Dyēus or as stated earlier derives from *Diwōnā.
Zis - The Messapic Equivalent of Dyeus