Historical manga enjoys a good position among the various genres out there, and while it is not one of the most popular ones, well done it can be genuinely epic and transcendental. Examples like Vinland Saga, Vagabond, The Rose Of Versailles and Kingdom are some of the best known. However, and before getting into the review itself, I have noticed that many manga call themselves "historical" without really being so, confusing the genre, and making the search for those who are only interested in historical manga as such cumbersome. So, what defines and differentiates a historical manga from those that, despite the similarities, are not? You will find many manga being called "historical" that are not; it does not matter, for example, that Battle Tendency takes place in the 30's, that does not make it a historical manga, or that Monster covers and takes place in certain historical periods of the 20th century, getting involved in certain historical issues, we just all know that it is not a historical manga. There are many examples of this, but at the same time this helps us understand what is a historical manga and what is not:
A historical manga is one that, takes place in a certain historical period, whose story is directly affected by said period, the characters act and are entangled by said contexts, and the story itself seeks to encompass and exploit such historical time and place. It is not enough if a story is set in a time period when this does not seem to affect the story and the characters, and it is not really interested in history, it only seeks to use it to justify certain aspects of the work.

Having made this introduction, I will move on to the actual review:
After expressing the previous points, Cesare appears, which, before going into deep details, is the most "pure" historical manga that I have found. Any work about history will seek to balance the historical aspect with a bit of fiction so as not to overwhelm the reader. Cesare does not care much about that.
This manga covers the historical period of the last years of the 15th century and the beginning of the 16th century in Italy; you know, the end of the Middle Ages and the beginning of the Modern Era with the Renaissance. More specifically, the story follows the infamous and well-known Spanish Borgia family, especially the early years of the famous Cesare Borgia in his days at the University of Pisa.
But let's get to the point with the strongest aspect in this manga: the artwork. The art is superb, orgasmic I would say. It can easily enter the top 10 mangas with best art. You may not get hooked on the plot but you will stay for the terrific art; it is incredible how it captures the essence of Italy in the Renaissance.
I could even say that simply because of the art it could already be awarded a “Pass”, regardless of the story. But let's move on to that point, perhaps the most problematic: Not everyone will love the story and its pace. When I said that Cesare is not interested in balancing history and entertainment, I meant it. This manga is just a justification to talk about history, pure and simple. I'm telling you right now that at a certain moment there are three chapters in a row just about a conversation about history. And even if you are a hardcore history lover you will find some problematic points in the reading of the story, specifically regarding its protagonist: although Cesare Borgia is the de facto protagonist, Angelo, a new Florentine student at the University of Pisa is the "official" protagonist, the viewer by which we will observe the story. And here is one of the most negative points, at least at the beginning of the manga: Angelo is a weak character, uninteresting, and quite hypocritical: I don't blame him for being enamored with Cesare and with every Spanish character, they are the stars in this manga, but not to the point of betraying his own and feeling alien to his own countrymen. It just doesn't work.
Another trouble point may be the reader's expectation: a story about the Borgia family? The Game of Thrones of manga! Well, not exactly. The story does revolve around political intrigues, philosophy, religion, and war themes, as well as hinting at shady issues, such as the slight implication of incest - Cesare and his young sister Lucrecia - but it does so in a serious, academic way, not interested in making it "exciting" for modern audiences.
There are many moments when you wish many other things to happen on another level, but you will have to be painfully patient.
Still, there comes a time where you reconcile yourself to the story, its content and form and really immerse yourself in it, and there it becomes great.
There are many well-known faces, in addition, Christopher Columbus, Leonardo Da Vinci, Nicolás Machiavelli, and other historical figures have their moment.
TL;DR
In short, it is a manga for true history lovers, and if you are not, you may stay for the art, but to be honest, it will get dense and dull.
My score so far is an 8, since the manga is not finished and it seems that it will not in a while.
If you like history in its high expression, check out Cesare.