Julius Caesar is a real name. Charlemagne is a real name plus a descriptor. Barbarossa is a nickname. “da Vinci” is just a place name — where Leonardo was born. He was illegitimate and had no last name. It’s like saying “from Aachen” and expecting people to know that you mean Charlemagne.
“It’s like saying “from Aachen” and expecting people to know that you mean Charlemagne.”
No, not when there is only one really famous person from Vinci and he is world renowned by that descriptor.