The Frontiers of Imperial Romeby David J. BreezePen & Sword Books, 2011As David Breeze points out in his terse, involving, and amazingly comprehensive new volume, The Frontiers of Imperial Rome, "for eight centuries, the Roman army was the pre-eminent fighting force in Europe. It did not acquire that position by sitting behind walls." Indeed, because Rome has for most of its history been aggressively territorial, one might almost say that the story of Rome is the story of its frontiers - their shape, their nature, their exigencies, and their fate. The events on those frontiers could of course have drastic significance to the whole of the Roman empire - invasions being the foremost example, naturally, but also near-invasions like the disaster in the Teutoberg Forest in AD 9 when three entire Roman legions and their auxiliaries were destroyed by massed German forces ("A younger Augustus," Breeze interestingly speculates, "would have bounced back, but by then the emperor was in his 70s and had lost his resilience. Germany was evacuated"). And the attitudes of the empire - and the men who ran it - could have drastic significance to the shape of Roman frontiers, as was dramatically seen in AD 117 when the new emperor Hadrian pulled back the empire's limits to the shape they'd held before the reign of his warlike predecessor Trajan. Always there were external dangers and internal pressures, making Rome's outlines fluctuate as though the empire were some massive single-celled organism.Like Caesar's Gaul, Breeze's book is divided into three parts: the ancient sources on which is inquiry rests (including a much wider and more systematic examination of inscriptions and other non-literary sources than you find in most books of this type), the frontiers themselves, and interpretations of many of the thorny questions debated by archeologists and historians of ancient border studies. In all three sections, Breeze displays a disarmingly broad cross-disciplinary learning and a talent for summary so deft and inclusive that the reader bombarded with facts without ever feeling overwhelmed by them. To put it mildly, many of Breeze's predecessors in this field of study haven't been so pithy (there were points during my first reading of Mommsen's The Provinces of the Roman Empire, for example, when I found myself hoping for a quick 'and then they all died' Hamlet-style conclusion as the chapters kept spooling outward and outward).Breeze covers all the different kinds of Roman frontier-works - desert, mountain, riverine, sea frontiers (including the Red Sea, the Black Sea, and the North Sea - reading these pages vividly reinforces just how big the Empire was), and he gives prolonged attention to places like the Rhine, North Africa, and Britain, where the Antonine Wall and of course Hadrian's Wall get extended consideration. In any book on Roman frontiers, Hadrian's Wall - stretching 80 miles from the River Tyne to Solway Firth - will necessarily be the star attraction, and it finds an expert chronicler in Breeze, as does the less-known Antonine Wall, about which Breeze prepared the successful bid to gain it World Heritage Site status.It's perhaps not natural to expect that somebody who can discourse as knowledgeably as Breeze on the working logistics of frontier forts and troop deployment would be equally interesting and readable on ancient literary sources, but nevertheless: this book instructs and entertains equally in all its separate spheres. When Breeze quotes a passage about the emperor Constantine written by Zosimus, he's able to add immediately his own rejoinder:

This is a splendid piece of hostile reporting. Diocletian may have renewed frontiers, but he did not invent them as the passage implies, nor did Constantine remove all soldiers; rather, he built on Diocletian's creations, including the field armies.

Breeze shapes his narrative almost as an ongoing dialogue with all experts in the field, so that the reader feels included in the flow of recent research instead of merely instructed about it. And Breeze is always on hand to smooth out the technicalities and provide expert summaries, as when he's discussing Hadrian's Wall:

The relationship between the soldiers on the barrier and those in the forts behind has been emphasized by the recent work by Poulter on how the Wall was originally surveyed. He has pointed out that when the base line had to move to negotiate a feature in the landscape, it moved to the south. This was presumably to allow the soldiers to remain in contact with the existing forts in the south. It was for this reason that the Wall was placed on the south side of the ridges along which it ran; from the point of view of the soldiers in the forts, the Wall stood on the skyline.

Our author seems to have read every single word of the ancient sources that touch on his field, and at every turn he gives us quick, expert elaboration, as when he points out that the creation of linear barrier-lines in support of frontier forts may be datable to the emperor Hadrian but then makes sure we have the bigger picture:

I should also be noted that linear barriers were in the Roman military portfolio; for example, Crassus sought to control Spartacus by the construction of a wall, and Caesar had constructed a linear barrier to channel movement in southern Gaul.

Virtually every consideration of Roman frontier studies is given time and space in these pages, and the gamut of the empire is dealt with, from the earliest days under Augustus to the fragmenting of the empire centuries later, when suddenly many of those bristling, well-run forts and walls found themselves islands under siege. And the whole thing is extremely well-served by Pen & Sword Books, which has created a heavy, durably-made volume of slick, high-quality pages and lavish illustrations. The result of this book-crafting care and Breeze's erudition is a near-perfect example of specialized military history done for a popular audience. Students of Roman history will certainly want a copy.