>It's like (today or 18th century, does not matter) some African dude showing up in the middle of a busy European city center yelling "I discovered Europe!"
Imagine you self-fund your own voyage to Mars. You descend into a cave and find a city full of humanoid Martians. Do you think it would be inappropriate for you to exclaim, "I discovered Submartia!"?
Go medieval enough, and South Africa is about as remote as Mars.