Rosettes castle and Rocca Calascio

[Rafal]

And the castle in the original source, even if inspired by some real castle, was already altered by the artist who drew it.

Slightly offtopic, let me show you some pictures from De Balneis Puteolanis. They present the same scene coming from 4 different (but related) manuscripts:
   

Notice how the building in the top right corner changes between the versions.

I would say medieval artists weren't very keen on accuracy. They rather felt free to change the details just because.

And of course it makes problems for modern researchers when they try to identify something.