In a way, much of this book is miscast as an explanation of why the Western Roman Empire fell in the 400s. In order to give deep background, he starts very early in the process, with the Antonines, like Gibbon did. But since Gibbon had several large volumes to fill and his subject was the decline as well as the fall, this wasn’t a problem for him. And since Goldsworthy actually passes the fall and spends a chapter on the actions of the Eastern Emperors up to Justinian, the his theory of the causes of the fall gets lost in the narrative.
As a survey of the mid to late Western Empire, this book is first-rate. He has distilled the thin sources into a nice narrative package with rather more detail than a similar books. To me the book was worth reading for that alone.
But as a presentation of a new theory, or a new emphasis on the cause of Rome’s fall the book is lacking. Goldsworthy’s thesis is that the periodic Civil Wars progressively weakened Rome so that the external threats, which were essentially no stronger than in Julius Caesar’s time, could take the empire down.
There are a couple of problems with this analysis. The first is relative timing – the most chaotic and civil strife filled period was not near the end of the Empire’s life, but in the 235-284 AD period, two full centuries before the fall! At the height of the crisis, the empire had split into three sections, Gaul/Spain/England governing itself and the East was ruled by Palmyra. While Goldsworthy is correct in saying that these entities were self-help governments set up because of Rome’s inability to send aid rather than a true secessionist movement, his dismissing of their seriousness is unconvincing. If Rome had not quickly recovered under Aurelian to reclaim the areas, this division could have become permanent.
A similar thing happened in the 400s when Britannia and then Northern Gaul set up similar local defense zones when the power of the Empire ebbed. In this case, Rome never returned and the locals were eventually overwhelmed.
It is also questionable how much damage a civil war does in the long-term unless the diversion of effort allows external enemies to devastate or conquer territory. After all, in 50 years all the soldiers in the ancient army would be dead, be it in battle or of old age. Roman Civil Wars tended to avoid massive sieges or sacks of cities.
And his other main support, that external threats were unchanged I also find dubious and his arguments unconvincing. In the early empire, Arminius the great Hero who destroyed three legions was killed by his own people for wanting to become a king. In the 400s, there were several hegemonic German groups under a fairly powerful king on the Rhine alone – Franks, Vandals, Alamanni, and Burgundians. Each of these was organized enough to hold and possess portions of Roman land rather than dissipating into component groups. The Vandals remained a distinct entity for a century while occupying parts of Gaul, Spain, and finally North Africa. This certainly seems like a substantial difference in organization to me.
Goldsworthy does not really try and back up his assertions in any depth, so even as a defense of a theory I don’t follow, the book is disappointing.
If you want a good overview of the middle to late Roman Empire this is a great book. As a study of the cause of the fall of the West, it is only of marginal use.