The Limits of Empire: The Roman Army in the East.

• Author: Roth, Jonathan

This is that rare book combining critical discussion of detail with a broad historical vision. Isaac's command of classical, Talmudic, and archaeological evidence is impressive and provides a solid base upon which he builds a carefully crafted argument. The Limits of Empire is well worth reading for its in-depth description of both the peace- and war-time activities of the Roman army in the East, but it is best understood as part of a sharp debate in Roman historiography over the question of "grand strategy" in Roman imperial military planning.

In many respects, this book is a rejoinder to a work by the military theorist Edward Luttwak,(1) which attempted to set out strategic concepts behind Roman military dispositions. Luttwak's ideas, and particularly the notion that the Romans possessed a sophisticated notion of strategic planning, have been very influential among Roman historians.

Isaac argues forcefully that Luttwak's view of a defensive Roman Empire, guarding its borders against constant barbarian threat, is a modern one and anachronistic. The Roman frontier was a much more amorphous concept than the rigid boundary suggested by Hadrian's Wall and the defensive systems in Germany and Africa, and Isaac points out that the Romans did not necessarily see a line of fortresses as a national boundary in the modern sense. Such structures may not have been primarily intended as defensive installations but might well have been placed for other purposes, such as controlling traffic and raising customs revenues.

Isaac perhaps takes this argument too far. As E. L. Wheeler has pointed out in a lengthy review (and vigorous defense) of Luttwak,(2) a fort can serve both external and internal security. Nevertheless, Isaac's emphasis on the police and administrative functions of the army are an important counter-weight to historical theories that see the military strictly in its war-making capacity.

The book's most dramatic argument is that the Romans had no "grand strategy" in the modern sense at all. Isaac notes that the Romans lacked any sort of military staff, intelligence service, and, most importantly, the map-making ability upon which all modern military and political planning is based. While there are ancient maps, such as the Peutinger Table and the Madaba Map, they lack scale, the most important element of modern cartography.

In any case, Isaac says, the Romans never had a defensive strategy and always saw their army as a potentially offensive...