it doesn't make any sense for him to be known as The Spaniard. There was no Spain during the rule of Roman Empire. The Iberian peninsula was called Hispania, not Spain. Although the word Spain was eventually derived from Hispania, the country called Spain didn't exist until the union of the Kingdoms of Aragon and Castille in 1469. So, a person from Hispania would not be called a Spaniard, cause there were no Spanish or Spain.
This is just a case of the producers and writers being historically obtuse.
[This message has been edited by HistoryMystery (edited 11-26-2017 @ 01:57 PM).]