*Dyḗus (lit. "daylight-sky-god"), also *Dyḗus ph₂tḗr (lit. "father daylight-sky-god"), is the reconstructed name of the daylight-sky god in Proto-Indo-European mythology. *Dyēus was conceived as a divine personification of the bright sky of the day and the seat of the gods, the *deywṓs. Associated with the vast diurnal sky and with the fertile rains, *Dyēus was often paired with *Dʰéǵʰōm, the Earth Mother, in a relationship of union and contrast. While its existence is not directly attested by archaeological or written materials, *Dyēus is considered by scholars the most securely reconstructed deity of the Indo-European pantheon, as identical formulas referring to him can be found among the subsequent Indo-European languages and myths of the Vedic Indo-Aryans, Latins, Greeks, Phrygians, Messapians, Thracians, Illyrians, Albanians and Hittites. Name Etymology The divine name *Dyēus stems from the root *dyeu-, denoting the "diurnal sky" or the "brightness of the day" (in contrast to the darkness of the night), ultimately deriving from *di or dei- ("to shine, be bright"). Cognates in Indo-European languages revolving around the concepts of "day", "sky" and "deity" and sharing the root *dyeu- as an etymon suggest that Dyēus was the vast and bright sky of the day conceived as a divine entity, such as Sanskrit dyumán- 'heavenly, shining, radiant'. A vṛddhi-derivative appears in *deywós ("celestial"), the common word for "god" in Proto-Indo-European. In classic Indo-European, associated with the late Khvalynsk culture (3900–3500), *Dyēus also had the meaning of "Heaven", whereas it denoted "god" in general (or the Sun-god in particular) in the Anatolian tradition. The suffix-derivative *diwyós ("divine") is also attested in Latin, Greek and Sanskrit. The noun ("day"), interpreted as a back-formation of *deywós, has descendant cognates in Vedic Sanskrit divé-dive ("day by day"), Latin Dies, goddess of the day and counterpart to Greek Hemera, Hittite siwat ("day"), Palaic Tīyat- ("Sun, day"), Ancient Greek endios ("midday"), Old Armenian tiw (տիւ, "bright day"), Old Irish ("nine-day period"), Welsh ("today"), or Slavic Poludnitsa ("Lady Midday"). While the Greek goddess Pandeia or Pandia (, "all brightness") may have been another name for the Moon Goddess Selene, her name still preserves the root *di-/*dei-, meaning "to shine, be bright". Epithets The most constant epithet associated with *Dyēus is "father" (*ph2tḗr). The term "Father Dyēus" was inherited in the Vedic Dyáuṣ Pitṛ́, Greek Zeus Patēr, Illyrian Dei-pátrous, Roman Jupiter (*), even in the form of "dad" or "papa" in the Scythian Papaios for Zeus, or