The Roman Empire

Hadrian’s Wall ran 80 Roman miles, 73 modern miles, across northern Britain, and soldiers from three continents guarded it.

Augustus: an emperor who never said so

After Actium, Octavian held all real power, but he had seen what happened to Caesar. In 27 BCE he made a show of handing power back to the Senate, and the Senate gave him the honorary name Augustus, "the revered one". The Met dates the start of the empire to that year. He called himself princeps, "first citizen", kept the old offices and the Senate, and ruled through control of the army and the treasury. Historians call this system the principate. Augustus ruled until his death in 14 CE, more than forty years, long enough that few people remembered the Republic working. Under him and his successors came about two centuries of relative peace inside the frontiers, which writers later called the Pax Romana.

Emperors good and bad

The family of Augustus, the Julio-Claudians, gave Rome Tiberius, Caligula, Claudius, under whom the conquest of Britain began in 43 CE, and Nero, whose reign saw the great fire of Rome in 64 CE. After Nero’s suicide, four men claimed the throne in 69 CE, and Vespasian won. He began the Colosseum in 72 CE, and his son Titus finished it in 80 CE. In 79 CE, early in Titus’s reign, Mount Vesuvius buried Pompeii and Herculaneum. In the 2nd century a series of capable emperors chose heirs by adoption. Trajan, born in Spain, conquered Dacia, roughly modern Romania, and pushed into Mesopotamia; at his death in 117 CE the empire was the largest it would ever be. His successor Hadrian gave up the newest eastern gains and fortified the frontiers instead.

A frontier you can still walk

Hadrian visited Britain in 122 CE, and according to English Heritage, the building of his wall probably began that year and took at least six years. It ran 73 miles, or 80 Roman miles, from Wallsend on the Tyne to Bowness-on-Solway. The finished system had 16 forts, 80 milecastles, one roughly every Roman mile, and 156 turrets, with a ditch in front and an earthwork, the Vallum, behind. At its tallest the wall stood about 4.6 metres. It was less a barrier against invasion than a way to control movement and trade across the frontier. The soldiers were mostly auxiliaries recruited from provinces across Europe, Africa and Asia.

Crisis and a new kind of empire

In 212 CE the emperor Caracalla gave Roman citizenship to all free men in the empire. Soon after, the empire entered half a century of crisis, from 235 to 284 CE, with plague, inflation, invasions and a long series of short-lived emperors, most of them generals killed by their own troops. Diocletian, emperor from 284 CE, restored order by splitting the job: from 293 CE four rulers, two senior and two junior, shared the empire. Constantine reunited it, won the Battle of the Milvian Bridge in 312 CE under a Christian sign, and with his co-emperor granted Christians freedom of worship in 313 CE. In 330 CE he dedicated a new capital on the site of Byzantium: Constantinople, today Istanbul. Latin remained the language of the west and Greek of the east, a split that would shape the future.