I hear people say things like this a lot, and it's always jarring to me to think where they get that impression, because it's quite ahistorical. Going back actually all the way to antiquity (Romans, Vikings), there was far more visible diversity across Europe than what you typically see in cinematic portrayals. The homogenous image people have is a product of Hollywood, not a reflection of what the time period was actually like.

Anyway, your statement is objectively incorrect, even beyond the obvious hyperbole. There were plenty of Black people in Italy in that time period, enough that it's really not shocking to imagine one as a magical character in a literal fairy tale.