1911 Encyclopædia Britannica/Hesperus

HESPERUS (Gr. Ἕσπερος, Lat. Vesper), the evening star, son or brother of Atlas. According to Diodorus Siculus (iii. 60, iv. 27), he ascended Mount Atlas to observe the motions of the stars, and was suddenly swept away by a whirlwind. Ever afterwards he was honoured as a god, and the most brilliant star in the heavens was called by his name. Although as a mythological personality he is regarded as distinct from Phosphoros or Heosphoros (Lat. Lucifer), the morning star or bringer of light, the son of Astraeus (or Cephalus) and Eos, the two stars were early identified by the Greeks.

Diog. Laërt. viii. 1. 14; Cicero, De nat. deorum, ii. 20; Pliny, Nat. Hist. ii. 6 [8].