The evolution of the Roman military machine

Review of The Complete Roman Army by Adrian Goldsworthy

This book follows the development of the Roman Army from its mythic founding (in 753 BCE) to the collapse of the West in the 5^th century CE, over nearly 700 years. The writing is dense and to the point, skipping narrative treatment for hard-nosed analysis. What made the Roman Army unique”? How did it adapt to different circumstances? What was interplay of its relation to the political institutions, both as protector and source of change? Finally, what is its legacy?

For the first few centuries, the Roman Army was essentially a citizens' militia, drawn from the landed classes (largely farmers for the infantry) and commanded by the patrician aristocracy in the Senate. They were not particularly well organized, rushing into battle to establish heroic honor, much like the soldiers of Alexander the Great. But there were differences from other empires: Rome always fought to win decisively instead of seeking tactical advantage. In addition,  rather than subjugating conquered peoples, they attempted to co-op them, first by leaving their elites in charge and then by employing them as foot soldiers.

As Rome consolidated her hold over central and southern Italy, her armies also began to organize themselves into larger units, particularly after the city was occupied by the Celts in the 5^th century BCE. In the first excursion outside of Italy (to Sicily to fight Carthage in 3^rd century BCE), Rome developed a navy, which with relentless determination they rebuilt several times after disastrous losses. In the following war with Carthage, under attack from Hannibal, the Roman legions developed a new flexibility and control, enabling them to also fight the Hellenistic Greeks; in both of these conflicts, the Romans would not back down in the face of seemingly decisive reversals and would continue to fight even when its adversaries had overwhelming advantage, refusing deals that would maintain the status quo at lower cost. Eventually, their enemies were beaten and incorporated or annihilated in the case of Carthage, a Phoenician culture that seemed to be reborn at each opportunity.

Rome emerged as the greatest power in the Mediterranean in the 2^nd century BCE, supremely confident and striking fear into its potential enemies. It was the Roman Republic's golden age, a period of rapid expansion. Goldsworthy goes into great detail about the technical organization, which I will not attempt to recapitulate (e.g. you can learn how many men a centurion commanded and what his job was, etc.). Suffice to say, they developed a formation with flexible lines; younger soldiers began in front, followed by middling ones, and finally, older ones who were experienced and held in reserve. They could form and reform, allow openings for purposes of maneuver and entrapment, and rotated formation to keep troops fresh. They were flanked by cavalries staffed by equestrians (those wealthy enough to equip themselves, but not of senatorial rank). Finally, the Army had solid supply lines, supported by huge investment from the society, and a great flexibility to adapt to changing circumstances.

In spite of its vast organization, republican Rome was run very much as a city state, with virtually no bureaucracy and a kind of amateurism in the ever-changing chief executives (consuls), who served only a year and often had to lead their campaigns within that time frame, though they could be voted proconsul to extend their generalships in case of need. The timeframe tended to limit their vision and staying power, leading often to the mistreatment of their colonial charges. This amateurism led to the social wars (91-87 BCE), the last great rebellion on the Italian peninsula with autonomous allies of related indigenous groups. To meet it and the many challenges in disparate parts of the growing empire (Celts/Germans in Northern Europe and Jugurtha in North Africa), a series of great generals (in particular Caius Marius, 157-86 BCE) began to professionalize the army.

Though command remained largely in the hands of Senators or the aristocratic families, poor men replaced the yeomen farmers who heretofore had had to fight at direct expense to themselves, leading to neglect of their farms. This had terrible economic and political ramifications. First, at least in the later official line, professionalization of the army lessened the sense of civic obligation and consciousness of the troops, who had less at stake than land-owning farmers with some idea of the "nation"; hence the new soldiers did not view the republic as religiously inviolate. Second, with the Senate's refusal for political reasons to take care of retired veterans, soldiers began to give their loyalty exclusively to their generals. Third, the army was becoming autonomous, a power center in its own right that could operate on a long-term time horizon. Soon they would become the kingmakers. Thus, the legitimacy of the Republic gave way to fealty to generals, and terrible civil wars ensued, pitting Marius against Sulla and Julius Caesar against Pompey, to name the biggest early ones.

Once the Republic was dead and Marc Antony finally defeated (30 BCE), the Emperor Augustus (r. 27 BCE to 14 CE) further professionalized the army, moving it into many roles of administration and policing, ensconcing it even further into civil society. Here, his praetorian guard – the elite military protectors of the Emperor in Rome itself – moved into a new position of power which was to last for over 300 years.

This represented a fundamental political shakeup, eliminating the old aristocratic families from their traditional "rights" as commanders and colonial potentates; while gifted with privileged access, aristocrats would have to earn their places now by skill rather than the politics of oligarchy. Once Augustus established the Imperium, which posited that Rome has ended its policy of conquest (later to be revisited), Rome became an essentially defensive power, preserving its holdings rather than expanding without limit. It was no longer a question of seizing glory as it was to provide security, which had the obvious consequences: a new (and realistic) conservatism, a rolling back of ambitions, and a fortified posture. Permanent garrisons and militarized borders began to be built in stone, such as Hadrian's wall, and the army was reorganized for these contingencies, perhaps with over-confidence. Political power then moved to huge provincial garrisons outside of Rome, which became a ceremonial capitol.

As generals became more powerful in their long-term remote outposts, they became direct threats to the authority of the emperor, who needed to be constantly on the move to deal with problems as they arose. This created a paradox: the emperor needed good soldiers, but couldn't trust them. After the golden age of the Empire with the assassination of Marcus Aurelius, a terrible period of instability began, with changes in leadership every few years. Generals were elevated by their troops to emperor, essentially usurpers by acclamation, initiating innumerable civil wars that depleted manpower and resources. Meanwhile, the borders became less secure and adversaries such as the Germanic tribes learned to adopt many of the old tactics of the Roman army.

It was only with Diocletian that Rome recovered for a time. Interestingly, as an Albanian, he was one of the first commanders who was not of the Roman aristocracy, but a new man elevated purely by his competence. The army, at last, was becoming wholly professional. This also enabled Diocletian to reorganize the entire society around the army, with a more accurate census and even distributed taxes instead of local levies in times of need; he also created co-emperors he trusted, allowing them to act competently and without fear of political reprisal. He eliminated the Praetorian Guard, removing a crucial political destabilizing force. He also remolded the bureaucracy to service the army. Diocletian moved the border outposts farther in for mobility, so that they could strike rapidly wherever there was trouble and lessened the necessity of protecting an impossibly long frontier.

Except for the Parthians, Huns, and a few others, military engagement against barbarians most often became an affair of relatively small raiding parties, which the Roman army learned to counter quickly. Unfortunately, this system proved unsustainable, and civil wars multiplied at the moment of population decline and increasing use of barbarian troops and mercenaries. Several poles of independent power centers established themselves in the Roman west, leading to a breakdown in the military system through lack of investment and loss of faith in the invincibility to the army. When it collapsed, it did so very quickly. (This does not explain the fall of Rome, that would take another book.)

This makes for fascinating reading for the history buff. There were many points of Roman history that I saw clearly for the first time and even some questioning of accepted wisdom. It is the performance of a master of popularization that is also accurate as a scholarly work. Goldsworthy writes in the most elegantly lucid prose. I have no fundamental criticisms of the book.