Head of Zeus (2018) h/b 192pp £18.99 (ISBN 9781784974718)

Hadrian’s Wall is the largest surviving monument of the Roman Empire, standing in the furthest flung region of that Empire along the remote northern frontier. Since, despite repeated attempts, Rome never succeeded in conquering Scotland, the wall served as a military base. It housed troops who patrolled the frontier for some three centuries. The original plan was that most of the troops would be housed in forts along Stanegate Road, which lay somewhat to the south of the wall. That plan changed at an early date. Substantial new forts were built on the line of the wall. Those at Housesteads and Birdoswald are still well worth visiting.

The two early chapters provide context. Chapter 1 is a brief account of Roman Britain. Chapter 2 focuses on Hadrian and his grand design for the wall. The meat of the book is in chapters 3 to 8. The wall was 120 kilometres long. The western section was originally built of turf, timber and earth, but later rebuilt in stone. The central and eastern sections were always in stone. The wall had both broad and narrow sections. Even the narrow sections were wide enough to accommodate a walkway along the top, but it is speculation whether such a walkway existed. Small fortlets (‘milecastles’) were built along the length of the wall at intervals of one Roman mile. In each stretch of wall between the milecastles, there were two turrets where soldiers on guard duty were posted. There was an extra turret between milecastles 39 and 40, which guarded the entrance to a pass. The remains of dice and gaming boards have been found inside the turrets. This suggests that the occupants enjoyed their leisure. Or perhaps they gambled when they were meant to be keeping watch.

The central section of the wall stood on tall crags, which made any fortification to the north both impossible and unnecessary. Along the rest of the wall, however, a ditch was dug on the north side. The gap between the wall and the ditch, known as the ‘berm’, was about 6 metres wide. The spoil thrown up from digging the ditch was piled on the north side to create a mound.

After the forts had been built, a wide flat-bottomed ditch was excavated on the south side of the wall. The material excavated was placed on both sides to form two continuous mounds, each about 9 metres from the ditch. Bede (c. AD 700) called this entire earthwork the vallum, meaning rampart. It seems a bit odd to call a ditch a rampart, but Bede is highly regarded and everyone has followed suit. After Hadrian died, his successor Antoninus Pius abandoned the wall and built a new one between the Forth and the Clyde. The Romans held that new frontier for only a few years, before returning south and recommissioning Hadrian’s Wall.

The purposes which Hadrian’s Wall served and its military value (if any) have been the subject of countless learned articles and papers. For good reason, G. does not enter into that debate. Instead he states his own view, which is that the wall had three main functions. First, it enabled the Roman authorities to monitor all movements across the frontier. Secondly, it was a military base for responding to a serious military threat of attacks from the north. Thirdly, it enabled the Romans to intercept raids. One altar inscription found at Hexham (RIB I, 1142) records that a cavalry unit had slaughtered a band of Corionotatae. But the wall probably had other functions as well. It enabled the authorities to levy import and export taxes (portoria) on all goods entering or leaving the province. Also, it was a monumental display of Rome’s might: the architecture was more elaborate than necessary for strictly military purposes.

Hadrian’s Wall is now a UNESCO World Heritage Site. Most people who walk it (including this reviewer) carry the National Trail Guide, which identifies points of interest and convenient places for overnight stops. From now on, however, anyone exploring the wall should also carry Adrian Goldsworthy’s excellent book. This book is well written and eminently readable, packed with interesting historical information. Of only modest size, it will readily fit into any shoulder bag or rucksack.

Rupert Jackson