The enemy within

On the 9 August 378 AD near Adrianople in Thrace the Roman army of the East was massacred and the Emperor Valens left dead on the battlefield by an army of barbarian Goths. It was, as Alessandro Barbero’s title claims, ‘The Day of the Barbarians’. He gives a highly readable account of the campaign and its consequences for an empire that stretched from Hadrian’s Wall to the fortresses on the Rhine, the Danube and the Tigris. It included what is now Turkey and the Middle East, Egypt and a strip of territory along the southern shore of the Mediterranean. Beyond the frontier lay the restive German barbarian tribes and the armies of Rome’s great rival, the Persian empire.

The intelligent reader of Gibbon’s Decline and Fall of the Roman Empire must deduce that it was victim of what modern historians have called ‘imperial overstretch’. It lacked the economic and financial, above all the man power, to sustain a vast empire.