The armies of Imperial Rome, and the 500-year history of the empire which they won and defended, are the shared foundation of the whole Western military tradition. There is no simple explanation for the access of vigour



through which a nation rises to seize its historical hour of dominance; we can never know "why", but can sometimes puzzle over the "how". In the 8th Century BC Rome was an obscure village guarding a river crossing in north-east Italy. She threw of Etruscan rule in the 6th Century, and herself dominated the whole Italian peninsula by the mid-3rd Century. Between the 260s and 140s BC she destroyed the great western Mediterranean empire of Carthage, and came to dominate Greece, Asia Minor and Egypt. By 120 AD Rome's rule extended from the Atlantic almost to the Caspian, from northern England to southern Iraq. Despite catastrophic setbacks she remained the single strongest power in the Western world, and its only "modern" military machine, until the early 5th Century AD. She

achieved this record, unique in history, with an army which until the 4th Century never exceeded about 320,000 infantry and60,000 cavalry.

The Roman legionary was the first soldier in Western history, and the only true soldier in a world of warriors or, at best, short-term mercenaries. He was a professional, long-service infantryman, paid wages by the state; and serving that state, wherever it sent him, in the ranks of permanent tactical units of uniform strength and organisation. He received uniform armour,field equipment and weapons, and was uniformly trained in their use. He was led by professional officers following a uniform career structure - the centurions, that unique pool of fightingmen who provided Rome with her invaluable continuity of experienced combat leadership.

The legionary was the luxury aforded by an enormously rich mercantile state, whose centralised, bureaucratic government invested its surplus revenues in a military machine designed to increase its territory and wealth. The legionary's enemies were, almost invariably, tribal warriors - pastoral or agricultural peoples for whom warfare could only be intermittent. They had no command structure or culture of discipline beyond temporary personal loyalty to a chieftain; no state resources, and thus no consistent standard of equipment or functioning logistics; no systematic tactical training; no systems of communication or coordinated control. Personal courage, strength and numbers could not outweigh these handicaps when faced by a professional army fighting under circumstances of its own choosing. The legions did not always enjoy this choice, however; and from the 3rd Century onwards they were increasingly forced to respond to the enemy's initiative, with increasingly dispiriting

results.

The army of the Republic, up to the late 2nd Century BC, was raised annually, partly by a levy of Roman citizens meeting a minimum property qualification, and partly from allied peoples fulfilling treaty obligations. The citizen levy was organised in "legions" - units between 4,000 and 5,000 strong. Each was divided internally, by age and standard of equipment, into three classes of heavy infantry and a fourth class of light skirmishers,plus some 300 aristocratic cavalry. Each legion was also divided into 60 tactical sub- units or "centuries", led by elected officers"centurions"; two centuries formed a "maniple".