Tertia is from the Latin tertius (third). **Aemilia Tertia (c. 230-162 BCE)** was the noble Roman matron and **wife of Scipio Africanus**, the conqueror of Hannibal — mother of Cornelia Africana, who in turn was mother of the Gracchi brothers. **Held together three generations of Rome's most influential family.**
The Roman convention: third daughters often took ordinal names.
Tertia reduces to nine — the number of Roman matron.