Hadrian's Wall (Latin: Vallum Hadriani), also known as the Roman Wall, Picts' Wall, or Vallum Aelium in Latin, is a former defensive fortification of the Roman province of Britannia, begun in AD 122 in the reign of the Emperor Hadrian.

Hadrian’s Wall (Vallum Hadriani, as those who built it would have called it), also known as the Picts’ Wall, was a defensive sea-to-sea fortification built by Emperor Hadrian in Roman Britannia. It was a Roman frontier, which historians now call Līmes. It was one of several frontiers he constructed all over the empire.

In about 122 AD, Emperor Hadrian ordered a wall to be built between the Solway and the Tyne to guard the north-west boundary of the Roman Empire. It was built within about six years and measured some 120km long, separating the Romans from the Caledonian tribes north of the wall, whom they often fought.

Hadrian’s Wall is the remains of stone fortifications built by the Roman Empire following its conquest of Britain in the second century A.D. The original structure stretched more than 70 miles across the northern English countryside from the River Tyne near the city of Newcastle and the North Sea, west to the Irish Sea.