They are fairly low res, being done for small icons in a game.
That's probably because the pointed top enclosed helmet came in a bit later than the era of the crusades, I got this a bit wrong. For some reason they went from pointy-topped Norman-type 'nasal helmets' to flat topped 'greathelms' to pointy topped 'sugar loaf' helmets.
I think it's made clear in the novel that Count Dracula the vampire was the historical Dracula, even though it may have been an afterthought (accompanying the name change). Dracula talks about himself (one can surmise) as though he were talking about an ancestor, and it fits the history of Vlad the Impaler reasonably well. The historical Dracula probably was in Istanbul, incidentally, he was brought up in the Turkish court as a hostage (I assume that was shortly after the fall of Constantinople), along with his brother who eventually betrayed him. I seem to recall the novel alludes to that betrayal.
Nicely done. The style reminds me of Dan Dos Santos.