Here's the castle depicted: https://en.wikipedia.org/wiki/Bel%C3%A9m_Tower

PersonalFowl said in comment #2626562:

Here's the castle depicted: https://en.wikipedia.org/wiki/Bel%C3%A9m_Tower

Seriously how the fuck do you recognize that? I only know it because it inspired Portuguese architecture in Age of Empires 2, but otherwise, I'd likely be lost as to whether it's Portuguese, Spanish, or South-French.

Machine translated the commentary; it lists the tower by name. A lot of this artist's works have little details in the commentary.