What is the modern fantasy genre may arguably be said to have been derived from historical fiction. After all, much of classical fantasy was derived from the myths and legends of times gone by, and for a long time (arguably to this day), fantasy was significantly stuck in twelfth century Europe. The genre has since expanded far beyond those historical beginnings, with subgenres like alternative world fantasy that are set in completely different universes, with their own laws of physics, and with characters that sometimes aren't human at all. However, given that heritage, it perhaps should not be terribly surprising that a historical fiction novel about the Wars of the Roses would read more like fantasy than anything else.
At this point, I'm going to assume that you've already read my reviews for Checkmate and The Ringed Castle, so you should know that this review is going to talk about things like how beautiful Dorothy Dunnett's writing is, how fascinating her tragic antihero is, and how seamlessly the historical context and geopolitical maneuvering is blended with the fictional story of Sir Francis Crawford comte de Lymond and Seveigny, because those characteristics were not unique to the final two books; they were the defining traits of the entire series. One day, I'll have been doing this site long enough that I won't have to shoehorn in reviews of the previous books in the series that I read before the site was up when I do these series reviews, but that isn't today.
Honestly, I'm not even quite sure where to begin reviewing this book (it probably doesn't help that I started reading this series years ago, long before I started consistently reviewing books on this website). I will do a full series review after reviewing Checkmate, but let's focus for now on The Ringed Castle. To put it in as few of words as possible, I loved everything about this book, and not just because my fiancee bought the series for me. It's sort of like what would happen if you took a highly educated Jack Sparrow, and plopped him into the middle of Lord of the Rings level writing, and set the entire thing to the beat of 16th century Russia, but that doesn't even begin to do it justice.