Of Latin and Greek origin.
These names have a common origin. From the Greek word “ίουλος” (ioulos), meaning the first facial hair of youngsters.
Also associated with Jupiter, the Roman god of the sky, king of the gods in ancient Roman religion.
Additional information about the Ancient Roman naming system:
According to the Roman naming rules, the basic elements of Roman names were three. A “praenomen”, a “nomen”, and a “cognomen”.
A “praenomen” was the first name, indicating the personal name.
A “nomen” was the second name, indicating the ‘gens’ to which the bearer of the name belonged to. Gens, meaning the group of families sharing a common “nomen”.
“Nomen” would stand as the group of loosely connected families claiming common ancestors. “Nomen” were always patrilinear, meaning from the father.
A “cognomen” was the third name and was something like the surname. Cognomina (plural of cognomen) were usually inherited. They were rarely given to the bearer by general consensus by the prominent members of the community.
There were several types of “cognomina”, such as geographical, adoptive, occupational, etc. In very rare cases the “cognomina” could be metronymic, meaning from the mother’s “nomen”.