Zeus the nominative is ("Zeús"). It is inflected as follows: vocative: (""); accusative: (); genitive: (); dative: (). Diogenes Laertius quotes Pherecydes of Syros as spelling the name, . "Zeus" is the Greek continuation of *"," the name of the Proto-Indo-European god of the daytime sky, also called *' ("Sky Father"). The god is known under this name in the Rigveda (Vedic Sanskrit "Dyaus/Dyaus Pita"), Latin (compare "Jupiter", from "Iuppiter", deriving from the Proto-Indo-European vocative *'), deriving from the root *"dyeu"- ("to shine", and in its many derivatives, "sky, heaven, god"). Zeus is the only deity in the Olympic pantheon whose
Horned deity also represented the East and West of the Earth, and one of the titles of Ammon was "the two-horned." Alexander was depicted with the horns of Ammon as a result of his conquest of ancient Egypt in 332 BC, where the priesthood received him as the son of the god Ammon, who was identified by the ancient Greeks with Zeus, the King of the Gods. The combined deity Zeus-Ammon was a distinct figure in ancient Greek mythology. According to five historians of antiquity (Arrian, Curtius, Diodorus, Justin, and Plutarch), Alexander visited the Oracle of Ammon at Siwa in the Libyan