INTRODUCTION

There is an image of the Roman imperial army embedded in the popular consciousness and in the minds of many Roman military historians. It is an image with which all who read this book will be familiar. The Roman army is frequently portrayed and described as the first modern, professional army. The achievements of the soldiery in maintaining the frontiers of a vast empire almost unchanged for four centuries are lauded and the credit is given to the quality of the troops and Roman military organisation. Yet this vast empire, stretching from the south of Scotland to Arabia and from the deserts of Africa to the lands beyond the Danube, was mostly not acquired by this professionalised force. The Roman army of the early Republic was, like the armies of many other ancient city states, a citizen militia, gathered every summer to fight the enemies of the state in wars which sometimes appear more like extended bandit raids. Gradually, for reasons that are still hotly disputed, this army conquered Italy, defeated the superpower in the Western Mediterranean basin, Carthage, and then extended her power to the East, conquering first one and then the rest of the Hellenistic kingdoms created by the successors of Alexander the Great. In the meantime, the armies went West and North, establishing control of Southern Gaul, Spain and the North Balkans. In surges of conquest, Rome came to rule the lands around the Western Mediterranean and exercise hegemony over those encircling the Eastern Mediterranean. In the last great explosion of conquering energy at the end of the Republic, the armies of Pompey completed the conquest of the Hellenistic kingdoms, only Egypt maintaining a fragile independence under the last Ptolemies, and Caesar conquered Gaul and threatened the remote, semi-mythical island of Britain.