In 122 AD the emperor Hadrian visited Britain, a province that had been under Roman control for nearly a century but one that continued to be a source of trouble for the new rulers. Various tribes in Scotland remained wholly unconquered, and even in the more southerly parts of Britain, Celtic groups such as the Selgovae and Brigantes kept up their resistance. With these two tribes in mind especially, Hadrian ordered a wall to be built, and much of its ancient course remains visible today. To see an enlargement, press here.

Stretching some 80 miles from coast-to-coast, from the Irish Sea to the North Sea (to the city of Newcastle, a town in Roman times as well as now), the wall divided the Selgovae in the north from the Brigantes in the south, and it raised the stakes for any Celtic chieftain who sought to reconquer the island of Britain.

Both Roman soldiers and native Britons took part in building the wall, the most important parts of which were completed in about ten years. The next emperor, Antoninus Pius, decided to send his armies north of the wall and for push into Scotland; as had happened in the previous century, the Romans failed to subdue the most powerful tribes and instead built the Antonine Wall (c. 145 AD), which remained the most northerly Roman outpost for about the next forty years, after which the imperial border once again became Hadrian's Wall.

In some areas (e.g., much of the city of Newcastle), few traces of the wall remain. Midway between Newcastle and Carlisle, however, archeologists have found many artifacts and have reconstructed much of the original barrier. At every mile the Romans had built a fort and also two watchtowers between the forts. The traces of one of the "milecastles" is visible at left. Along with the fortifications of the wall itself came other structures including the vallum, a ditch running parallel to the south.

Once the wall was finished, it conferred economic as well as military advantages on the Romans. The gates allowed the army to monitor movements between the south and the north and also to collect taxes. Communities serving the garrisons sprang up at various points, and the growing need for food led to cultivation of nearby lands.

Hadrian's Wall did not always stop northern invaders, who at times may have bypassed it through naval maneuvers. Nevertheless, the value of the wall to the Romans is seen in the fact that they continued to repair it until the late fourth century. By 383, however, the cost of manning the wall had grown too great for an empire under threat from invaders closer to Rome, and in that year the legions left the wall forever.

Though much less extensive than the Great Wall of China, Hadrian's Wall had a similarly mixed record of success as defensive structures. On the one hand, both walls could hold at bay smaller armies and bands of robbers. On the other hand, highly determined invaders proved capable of overcoming the defenses and invading the territories to the south.

To see other pictures of the wall, press here.