At the outset of this review, I wish to mention that this book did not work very well for me.
The author (David Donachie, alias Jack Ludlow) has published a number of historical novels already, and while I have read a number of them already, I have not read them all by far. The ones I have read (The Conquest Series and the Crusade Series, both about the Hautevilles of Southern Italy) so far have a common characteristic: the author tends to "make up" quite a few things rather than strictly stick to the historical record. While this might suit some, it does at time lead to some strange results, although it worked mostly well for the two series mentioned above.
This tendency to "make it up" reaches extremes in this book, which is supposedly about the younger years of Belisarius, of which we know just about nothing. So the whole story is "made up" and the only pieces that are historical in what is more of an adventure story than anything else are those related to Emperor Anastasius, the chief of his guards (the future Emperor Justin), Justin's nephew (the future Justinian) and Vitalian the general. Even there, however, some elements may be questionable. Anastasius, for instance, was a competent manager who restored the finances of the Empire and increased the army's pay, rather than being the tight fisted and dithering Emperor that he is portrayed to be in this novel.
At other times, and throughout the book, I definitely got the impression that the author's background research for the novel was somewhat superficial. For instance, there were no such things as the Walls or the forum of "Theodoric", who was no Emperor. Instead, it should have read "Theodosius" (with two Emperors of that name, and it was under the reign of the second of them that the double Walls of Constantinople were built. There are also some curious (and historically questionable) statements made in the book, such as the one about the Anastasius' war against Persia having "not favoured the Empire" and being concluded with an "unsatisfactory peace". In fact, the war had initially gone badly for the East Romans who then reconquered lost territory over the Persians. The conflict was essentially a draw. Other elements, however, such as the campaign of Anastasius' nephew Hypathius, and his disastrous defeat at the hands of Valerian, do follow the sources more closely.
The other problem I had with this book is that I found the story largely implausible. Belisarius was not, and was never known as "the last Roman" of course. It was Aetius who was called the last of the Romans. In fact, it is not even certain that Belisarius was fully "Roman", contrary to what is shown in the book, especially at a time where many of the soldiers and quite a few of the officers was of "Barbarian" extraction. A related point, however, was that the exact meaning of being "Roman" was somewhat shifting and had been since the fourth century at least.
My main issue, however, is that we have a fourteen to fifteen year old Belisarius who becomes an NCO within Vitalian's rebel army - something that is rather incredible - and who then goes galloping back and forth on embassies between the Court and Vitalian. This read like a story for teeagers, at times, with the hero of course setting things right and exacting his revenge, but a rather mild and almost "nice" one, was, for me, simply unbelievable, slow paced, and almost boring at times. Two stars.