I should have paid closer attention to the foreground in this, but sitting in the front seat of the tourist bus I had limited ability to move around. If I cropped the image I would lose some of the details of the castle. While it might have been possible to clone out the markings on the bus window, I don't think there would be any point.
The previous image showed us travelling along the Corso Umberto I, approaching the equestrian monument of King Vittorio Emanuele II. From there we would have looped around to the right of that piazza, and now find ourselves on the Via Agostino Depretis. (For history hounds, Depretis was an Italian politician and statesman who was Prime Minister several times in the decade from 1876.)
We are now approaching the Castel Nuovo, also known as the Maschio Angioino, one of the landmark features of Napoli. It sits near the water, traditionally guarding the port. "Castel Nuovo" literally means "new castle", though it depends on your definition of "new". Construction of what would become this castle commenced in 1279 under Charles I of Anjou ("Anjou" being where the name "Angioino" derives from), though initially its design was as much royal home as military establishment. The form that we see today dates back to Alfonso V of Aragon (also known as Alfonso I of Naples), who conquered the throne in 1443. He completely rebuilt the castle to make it look more like the type of building that we associate with the word today.
Nonetheless, it was the "new" castle compared to the two that already existed in the city at the time.
Considering the revolving door of rulership that Naples found itself under for several hundred years, it would be difficult to list every ruler who ever resided here or, indeed, every famous person. These days it houses a museum which I would really like to go back and see at some point.