Gaius Iulius Caesar (name) - The nomen Gentile Iulius

The nomen Gentile Iulius

Virgil and his commentator Servius wrote that the gens Iulia had received their name Iulius from the family's common ancestor, Aeneas' son Ascanius, who was also known under his cognomen Iulus, which is a derivative of iulus, meaning "wooly worm". Such nicknames were typical for cognomina and were the base of old gentilician names. By tracing their descent from Aeneas, the Iulii belonged to the so-called "Trojan" families of Rome.

Weinstock (1971) made a case for Iullus being a diminutive, i.e. juvenescent theophoric name of Iovis, which used to be one of the older names of the god Iuppiter. Weinstock's argument however relies on a hypothetical intermediate form *Iovilus, and he stated himself that Iullus can't originally have been a theophoric name and could therefore only have become one at a secondary stage, after the Julians had established the identification of Iulus as their gentilician god Vediovis (also: Veiovis), who was a "young Iuppiter" himself. Therefore Alföldi (1975) is correct in rejecting this proposed etymological origin.

Members of the Julian family like their chronicler Lucius Caesar later connected the name Iulus with ἰοβόλος ("the good archer") and ἴουλος ("the youth whose first beard is growing"). This has however no etymological value and is only a retrofitting interpretation concernced with the earlier institution of the Vediovis-cult in Rome together with a statue of Iulus-Vediovis as a (possibly bearded) archer. Others derived Iulius from King Ilus, who was the founder of Ilion (Troy). Weinstock rightfully called these the "usual playful etymologies of no consequence".