Aden was actually a country. It’s also really close to Africa, but since it’s on the Arabian peninsula, it’s considered to be on the continent of Asia.
Since this is the Dope, where pedantry is a way of life, I have to say that based on the category title, “Mexico” would be a legitimate answer (an original colony of Spain), or even “Ostia” (one of the original colonies of the Roman Empire)