Ancient Rome · 117–138 CE
Why Did Hadrian Build a Wall? Hadrian and the Roman Peace
In short
- Hadrian gave up Trajan's farthest conquests and spent his reign strengthening and inspecting the frontiers.
- Hadrian's Wall was begun around 122, and the Pantheon, rebuilt in his reign, still stands.
- The Roman peace had a price: the Bar Kokhba revolt, which began in 132, was crushed with immense loss of life.
In 122 CE the emperor Hadrian came to the cold north of Britain, and soon soldiers of three legions were building a wall eighty Roman miles long across the island. An ancient biographer says its purpose was to separate the barbarians from the Romans.
The emperor who gave land back
Trajan died in August 117 on his way home from a war against Parthia. Hadrian, his relative and former ward, was governor of Syria, and the army there proclaimed him emperor. Trajan's widow, Plotina, announced that Trajan had adopted Hadrian on his deathbed. Some ancient writers doubted it.
Hadrian then made a decision that dismayed many Romans. Trajan had seized Mesopotamia, Assyria and Armenia, lands hard to hold and costly to garrison. Early in his reign Hadrian gave up the conquests beyond the Euphrates. Four senators of consular rank, among them Lusius Quietus, one of Trajan's leading generals, were executed for plotting; Hadrian denied wanting their deaths, but Romans held them against him.
An emperor on the road
Hadrian spent about half his reign away from Rome, touring the provinces from Britain to Egypt. He inspected forts, watched soldiers drill and tightened discipline. At Lambaesis in North Africa, an inscription of 128 CE preserves parts of the speeches he made to the legion and its auxiliary units after their exercises.
His idea of empire was not conquest but upkeep: roads, cities, temples, and a frontier that soldiers could actually hold. In Athens he completed the huge Temple of Olympian Zeus, begun some six and a half centuries earlier. He loved Greek culture so much that, his biographer says, some called him “Greekling”.
A wall at the edge
In 122 Hadrian visited Britain. The Historia Augusta says that there he corrected many abuses and built a wall eighty miles long to divide the Romans from the barbarians. Eighty Roman miles are about 73 modern miles, which matches the line that runs from Wallsend on the Tyne to Bowness on the Solway Firth.
The wall had a small gated fort, a milecastle, every Roman mile, with two turrets between each pair; larger forts for whole garrisons were added while it was being built. Many archaeologists think it was not meant to stop an army. It controlled movement, let patrols spot raiders and gave the troops a base. Around 142 the next emperor, Antoninus Pius, pushed north and built a shorter turf wall in Scotland, the Antonine Wall. It was abandoned within about a generation, and the frontier returned to Hadrian's line.
Concrete, marble and grief
In Rome, the Pantheon was rebuilt in Hadrian's reign, though work may have begun under Trajan. Its dome, 43 metres across and made of unreinforced concrete, is still the largest of its kind in the world, and its portico still carries the name of the original builder, Agrippa. Near Tivoli Hadrian built a vast villa with buildings named after places he had admired on his travels.
In 130, on a journey up the Nile, his young favourite Antinous died in the river. Hadrian, his biographer says, wept like a woman. He had Antinous honoured as a god, founded a city in his name, and filled the empire with his statues. Ancient writers disagree about the death itself: Hadrian wrote that Antinous fell into the Nile, while Cassius Dio believed he was sacrificed.
The price of peace
The Roman peace was not peaceful for everyone. Around 130 Hadrian visited Judaea and planned to refound Jerusalem, in ruins since 70, as a Roman colony called Aelia Capitolina. Cassius Dio blames that plan for the revolt that followed in 132; the Historia Augusta blames a ban on circumcision. Historians still argue. The rebels' leader was Simon bar Kosiba, hailed as Bar Kokhba, “son of the star”.
Rome had crushed the revolt by about 135. Cassius Dio claims that 580,000 Jewish men were killed in raids and battles and that 985 villages were destroyed, figures historians treat with caution. Jews were barred from Jerusalem, and the province was renamed Syria Palaestina. Hadrian died in July 138, after adopting Antoninus Pius as his heir. Edward Gibbon judged the years from 96 to 180, which include Hadrian's reign, the happiest in human history. Many of the people Rome ruled would have disagreed.
In their own words
“Having reformed the army quite in the manner of a monarch, he set out for Britain, and there he corrected many abuses and was the first to construct a wall, eighty miles in length, which was to separate the barbarians from the Romans.”
Historia Augusta, Life of Hadrian 11.2, late 4th century CE
Translation by David Magie (Loeb Classical Library, 1921); the sentence opens “And so, having reformed…”. The Historia Augusta is a collection of imperial biographies written long after the events under the names of six authors who are probably fictitious. Inscriptions and archaeology confirm that the wall was built under Hadrian from about 122.
Why it happened
- Trajan's conquests stretched the army thin and were hard to hold, so Hadrian chose to consolidate.
- Rome's peace depended on a professional army kept on the frontiers, paid for by provincial taxes.
- Imperial policy in Judaea, including the plan for Aelia Capitolina, provoked revolt among a people who had already lost Jerusalem in 70.
What happened next
- Apart from brief advances into Scotland, Hadrian's line remained the northern frontier of Roman Britain until Roman rule ended there in the early 5th century.
- The Bar Kokhba revolt ended in destruction and exile for many Jews, and shaped Jewish life in the diaspora.
- The empire held together under Hadrian's successors for another generation, but by the 370s Gothic armies were crossing the Danube. Read the story →
Why it still matters
Hadrian's Wall became a UNESCO World Heritage Site in 1987 and is now part of the international “Frontiers of the Roman Empire” site, together with the Upper German-Raetian Limes and the Antonine Wall. Walkers follow its whole line, coast to coast, on the 84-mile Hadrian's Wall Path national trail.
Key people
- Hadrian
- Roman emperor 117–138, who consolidated the empire's frontiers
- Trajan
- Hadrian's predecessor, under whom the empire reached its greatest extent in 117
- Antinous
- Young companion of Hadrian who drowned in the Nile in 130 and was deified
- Simon bar Kokhba
- Leader of the Jewish revolt against Rome that began in 132
Key terms
- Pax Romana
- “Roman peace”: the long period of relative stability under the emperors from Augustus to about 180 CE.
- Limes
- The fortified frontier of the Roman Empire, such as Hadrian's Wall or the German border.
- Milecastle
- A small gated fort built every Roman mile along Hadrian's Wall.
- Aelia Capitolina
- The Roman colony that Hadrian founded on the site of Jerusalem.
Test yourself
How long was Hadrian's Wall, according to the Historia Augusta?
- Forty miles
- Sixty miles
- Eighty miles
- A hundred and twenty miles
Show the answer
Eighty miles. The Historia Augusta says eighty miles. These were Roman miles of about 1,480 metres, so about 73 modern miles, which matches the surviving wall.
The full lesson in the app ends with 5 questions like this one.
Connected stories
- Pompeii: The Day Vesuvius Erupted: The empire's peace and prosperity, which let a town like Pompeii flourish, was what Hadrian worked to preserve.
- Augustus: How a Republic Became a Monarchy: Augustus left advice to keep the empire within its existing bounds; after Trajan's conquests, Hadrian returned to that policy and fortified the frontiers.
- The Fall of the Western Roman Empire: The frontiers he fortified would be tested and finally overwhelmed in the fourth and fifth centuries.
Frequently asked questions
Why did Hadrian stop expanding the Roman Empire?
Trajan's conquests stretched the army thin and were hard to hold, so Hadrian chose to consolidate. Rome's peace depended on a professional army kept on the frontiers, paid for by provincial taxes. Imperial policy in Judaea, including the plan for Aelia Capitolina, provoked revolt among a people who had already lost Jerusalem in 70.
What was the legacy of Hadrian's reign?
Apart from brief advances into Scotland, Hadrian's line remained the northern frontier of Roman Britain until Roman rule ended there in the early 5th century. The Bar Kokhba revolt ended in destruction and exile for many Jews, and shaped Jewish life in the diaspora. The empire held together under Hadrian's successors for another generation, but by the 370s Gothic armies were crossing the Danube.
How long was Hadrian's Wall, according to the Historia Augusta?
Eighty miles. The Historia Augusta says eighty miles. These were Roman miles of about 1,480 metres, so about 73 modern miles, which matches the surviving wall.
What is the main primary source for “Hadrian and the Roman Peace”?
Historia Augusta, Life of Hadrian 11.2 (late 4th century CE). Translation by David Magie (Loeb Classical Library, 1921); the sentence opens “And so, having reformed…”. The Historia Augusta is a collection of imperial biographies written long after the events under the names of six authors who are probably fictitious. Inscriptions and archaeology confirm that the wall was built under Hadrian from about 122.
Sources
- Historia Augusta, Life of Hadrian, translated by David Magie (Loeb, 1921)
- Cassius Dio, Roman History 69, translated by Earnest Cary (Loeb, 1925)
- Anthony R. Birley, Hadrian: The Restless Emperor (1997)
- Richard Hingley, Hadrian's Wall: A Life (2012)
Images are credited under each picture. Paintings and photographs come from public collections via Wikimedia Commons; scenes with no surviving image are marked as illustrations.
