The Roman emperor Hadrian (ad 117–38) ruled an empire the extent and coherence of which is beyond the wildest dreams of the European Union; it possessed a single currency and its territory extended from Scotland to the Sahara and from the Atlantic to Arabia. The entire Mediterranean basin for the first and only time in its history was controlled by a single power. How Rome transformed itself from a city state to an empire with territories on three continents is the theme of Patrica Southern’s history.

Initially Rome was a small Italian city state, but, under the pretence of securing its boundaries, from the sixth century bc onward the Romans started to control and conquer their neighbouring communities, which became self-governing colonies. After victory over Carthage in the first Punic War in 241 bc, Rome acquired the overseas provinces of Sicily, Sardinia and Corsica, which needed to be governed and garrisoned; so began its empire. After a second war with the Carthaginians, their captured Spain territory in 206 bc became another Roman province. Then after a series of wars in Greece the province of Macedonia was established in 148 bc. The third war with the Carthaginians ended in 146 bc with their defeat and their north African territory was transformed into a Roman province. The Romans had now eliminated their only serious commercial and military rival in the Mediterranean. In about 121 bc Transalpine Gaul was conquered. By 62 bc large areas of the eastern Mediterranean, including Bithynia, Cilicia, Pontus and Syria, were all under Roman rule. In 58–50 bc Julius Caesar completed the conquest of Gaul. In 30 bc Egypt and its territories were incorporated into the empire after a civil war. One important result of this civil war was the end of Republican government as the victorious Augustus became the first emperor in 27 bc. He was the first of a long series of elected (rather than hereditary) dictators. Augustus fought several campaigns to try and stabilise the empire’s frontiers along the Danube and the Rhine, which involved the conquest of more territory. These campaigns marked the start of a perennial problem that the Roman empire faced: many provinces lacked easily defendable frontiers. The preferred Roman policy was to bribe or placate hostile tribes living outside the empire, but if this did not work then the only other option was perpetual frontier warfare against the likes of the Germans, Parthians and Picts.

In ad 43 Britain was invaded. Next in ad 46 Thrace and a new Danube province, Noricum, were both annexed. Under Trajan (ad 98–117) occupied territory along the Danube became the province of Dacia, and, in the Middle East, Arabia was annexed. The empire had now reached its zenith. Trajan’s successor, Hadrian, performed a ‘momentous U-turn’ in terms of imperial policy. Instead of undertaking conquests, he now embarked on a programme of frontier consolidation and fortification, authorising the construction of ‘Hadrian’s Wall’ and defences in Germany. The army’s primary task from now on was to maintain the empire’s frontiers. One exception was a brief extension of Britain’s northern frontier in c ad 139–40, but by c 160 this new territory in Scotland was abandoned and the army reoccupied Hadrian’s Wall.

As the empire expanded, its standing army became the supreme power base that could appoint or depose emperors. When rival military fractions backed different candidates for post of emperor, civil war erupted. During the early Roman period (ad 0–200) there were periodic rebellions in Britain, Judea and elsewhere, but the majority of the empire’s provinces were relatively peaceful for long periods of time. The Romans were tolerant of local customs and religions, often using local rulers to govern portions of the empire. Provincial residents (who were not Roman citizens) were encouraged to join the Roman army as auxiliaries; sensibly, these troops served under Roman commanders far from their homeland to ensure their loyalty. The Romans had a relatively efficient system of provincial government and tax collection, and they promoted a policy of assimilation and cultural integration, often described as ‘Romanization’. One serious weakness of the empire was that efficient central government was largely dependent on the emperor, so if he was incompetent or weak then chaos and/or civil war were likely.

Over time more resources were required to defend the empire’s frontiers from multiple threats, and this permanent cost created financial problems. The military situation was worsened by various internal rebellions caused by ambitious generals or provincial officials declaring themselves emperor. Sometimes, these rebellions were successful, for example in ad 196 a general, Septimius Severus, became the undisputed emperor after winning a civil war. He immediately embarked on a series of campaigns to restore the empire’s frontiers, annexing Mesopotamia in ad 198 and extending the boundaries of the north African provinces.

After ad 230 there were many periods of political instability as repeated attempts were made by various generals to become emperor. These rebellions resulted in troops being withdrawn from the empire’s frontiers to fight in civil wars, which allowed the ‘barbarians’ (the name the Romans gave to people living outside their empire) to invade. There was an unsuccessful struggle ‘to keep hold of territory’, causing the abandonment of parts of some frontier provinces. Matters were made worse by economic decline, necessitating currency reform. In ad 286–7 Carausius, a fleet commander in Britain, was declared emperor by his troops and started another civil war. Roman rule in Britain was not restored until ad 296.

By ad 300 the empire, though weakened by economic stagnation and political instability, was still substantially intact, but the military situation was getting steadily worse as, when not embroiled in civil war, the Roman army struggled to cope with multiple invasions, a situation that became a catastrophe in ad 367. In an attempt to redress these problems during the early fourth century there was a complete reorganisation of the empire’s government and tax collection system. In ad 324 a new eastern capital Constantinople was established and subsequently the empire was administered (and latterly governed) as two separate units. In ad 410 the Goths sacked Rome, an event that is generally interpreted as the end of the western empire as a political entity, while the wealthier eastern empire carried on as Byzantium until 1453.

A series of chronological charts listing key events during the Republic, plus subsequent centuries, would have been very useful, as this book is intended for the general reader. Many of the later chapters adopt the reigns of emperors as subheadings. It would have been helpful to have included the dates of the reigns of each of these emperors in these headings, as this would have unobtrusively outlined the chronology of each period under discussion. Crucial to any understanding of the development of the Roman empire are maps. Unfortunately, the maps showing the location and extent of the various provinces at various chronological stages are inadequate: some of the lettering is too small to be easily readable; the labelling is poor; most maps have no scale-bar; tone could have been used to highlight the extent of individual provinces; and very few maps show the location of any cities, so the urban geography of the empire is underrepresented. For instance, map 13 illustrating the third century forts along the Rhine and Upper Danube has no labels, so the rivers and provinces represented cannot be identified.

While the text is a very informative and readable chronological narrative of complex events, packed with detail plus relevant archaeological data, the answers to some of the bigger questions, such as why Rome was so successful in the conquest and government of diverse territories for centuries, have got a bit lost in the narrative. Each chapter could have ended with a short discussion of its contents. The final chapter, however, is an overview of the various provinces in the fourth century and includes a discussion of the Romanization of Britain. One topic that is not discussed is the Roman empire’s legacy, including language, agricultural and technological innovation, numerous impressive archaeological monuments, roads and the creation of a network of urban centres, many of which were, like Londinium are, the ancestors of thriving communities today. The book provided me with a much clearer understanding of how the province of Britannia fitted into the empire and what an anomaly this remote and rebellious Atlantic province was. Perhaps this situation explains why centuries later we were never happy being part of the European Union.