Roman Naming, De-mystified!

Praenomen: A parent chose a praenomen for their child, generally from a finite list of praenomina.  Often, the praenomen of a child corresponded to birth order (ex. "prima" or "primus" for the first child, "quinta" or "quintus" for the 5th, etc.)
            -Within your family, you would be called by your praenomen

Nomen: This name indicated a family's gens or tribe.

Cognomen: This name was inherited from a son or daughter's father
            -Sons took the exact same cognomen as their father
            -Daughters took the genitive of their father's cognomen until marriage
            -A married woman took the genitive of her husband's cognomen after marriage
            -Outside of your family, you would be called by your cognomen (or your praenomen initial plus your cognomen: ex. "Caesar" or "G. Caesar")

What does this mean for...

...A son? He will have the same nomen and cognomen as his father, but a different praenomen

...A daughter? She will have the same nomen has her father, but the feminine form.  She will have the same cognomen as her father but in the genitive (showing that she is the daughter OF him).

...A married woman? Her cognomen will change to reflect her husband's cognomen (she takes on the genitive form of her husband's cognomen in place of her father's cognomen).

...Your siblings? They will have the same nomen as you (but girls will have feminine form) and same cognomen as you (but girls will have genitive rather than nominative form)

...Your cousins?  They will have the same nomen as you (but girls will have feminine form), but might have a different cognomen

Examples of masculine vs. feminine nomina:

-Cornelius vs. Cornelia

-Iulius vs. Iulia

**see? Nomina are 1st or 2nd declension!

Examples of nominative vs. genitive cognomina:

-Caesar vs. Caesaris

-Scipio vs. Scipionis

-Metellus vs. Metelli

**see? Cognomina are often (but not always) 3rd declension!