In Greek mythology, Hesperus /ˈhɛspərᵿs/ (Ancient Greek: Ἓσπερος Hesperos) is the Evening Star, the planet Venus in the evening. He is the son of the dawn goddess Eos (Roman Aurora) and is the half-brother of her other son, Phosphorus (also called Eosphorus; the "Morning Star"). Hesperus' Roman equivalent is Vesper (cf. "evening", "supper", "evening star", "west"). Hesperus' father was Cephalus, a mortal, while Phosphorus' was the star god Astraios.
Hesperus is the personification of the "evening star", the planet Venus in the evening. His name is sometimes conflated with the names for his brother, the personification of the planet as the "morning star" Eosphorus (Greek Ἐωσφόρος, "bearer of dawn") or Phosphorus (Ancient Greek: Φωσφόρος, "bearer of light", often translated as "Lucifer" in Latin), since they are all personifications of the same planet Venus. "Heosphoros" in the Greek Septuagint and "Lucifer" in Jerome's Latin Vulgate were used to translate the Hebrew "Helel" (Venus as the brilliant, bright or shining one), "son of Shahar (god) (Dawn)" in the Hebrew version of Isaiah 14:12.