The path of Hadrian's Wall was originally traced by a series of forts stretching from Carlisle in the West to Corbridge in the east, a line now called the Stanegate Frontier.  The forts were built during the reigns of Domitian, Nerva and Trajan, ca. AD 90-100. Apparently, this line failed to pacify the region as intended, and further steps were needed.

Construction of the wall commenced ca. AD 122, right around the time of the Emperor Hadrian's personal visit to Britannia.  It is unclear whether Hadrian brought Legio VI with him as a replacement for Legio IX Hispana, or whether it had come over a few years earlier (ca. AD 119-121).  In any case, Legio VI had already obtained considerable experience building fortifications along the Rhine frontier in the province of Germania and probably had a first-rate engineering and construction team in place.

At left, a Ron Embleton painting from Hadrian's Wall in the Days of the Romans (Embleton / Graham, 1984) shows the Emperor Hadrian and Platorius Nepos, legate of Legio VI Victrix, surveying a region through which the future wall will pass. Hadrian conceived of the wall as a means of stabilizing northern Britannia, which had been a hotbed of rebellion and unrest for decades.  Two prominent Celtic tribes, the Brigantes and the Selgovae, occupied the region and had never taken well to Roman domination. Hadrian decided to enforce the old Roman policy of "divide and rule."  His wall would split the Brigantes from the Selgovae and hopefully overawe and pacify the troublesome tribes. The map below, by English Heritage, shows how the wall is situated and locates points of interest (museums, etc.) that can be visited today.

All three Roman legions stationed in Britainnia, II Augusta, VI Victrix and XX Valeria Victrix, participated in constructing the wall, identifying their work for posterity by means of inscriptions along its length.  Below left is an illustration by Ron Embleton showing legionaries hard at work building a section of wall.  Built entirely of stone (an initial turf section in the west was replaced with stone by AD 158), the wall averaged eight feet thick and 15 feet high.  A large ditch 27 feet wide and 10 feet deep ran along the northern face.  Every Roman mile was marked by a gated opening guarded by a small fortlet called a "milecastle."  Two 20-foot towers spaced evenly between each milecastle provided a higher vantage for observation and signaling.  In addition, a series of 16 larger forts, some of which partially projected beyond the wall, were spaced along its length.  A crenellated parapet sentry walk may have topped the wall, but probably was not used as a fighting platform since it faced potentially hostile tribes along both sides. It was more likely used by regular patrols to keep an eye on and control movements.  A Roman road called the "Military Way" follows the wall along the south side to facilitate supply and communications. A second ditch called a vallum, 20 feet wide, 10 feet deep and with a flat bottom eight feet wide, dug some distance from the southern face of the wall, apparently filled a twofold purpose as a boundary line for the "militarized zone" and a literal "last ditch" line of defense.

More than two million tons of rock and soil had to be quarried and moved to build the wall.  Although the initial construction seems to have been carried out quickly (within four years), it was continuously modified, repaired and strengthened over the next two and a half centuries.

Built solely by legionaries, Hadrian's Wall was occupied by auxiliaries, or non-citizen soldiers.  Their numbers included both infantry and cavalry, and most of the milecastles and forts have stabling provisions.  About 9,500 soldiers manned the wall in most periods, although manpower  fluctuated depending on the threat level.  The three British legions were stationed at much larger fortresses scattered around the province, the closest being Legio VI Victrix's fortress at Eburacum (York) some 70 miles south of the wall. Below left, another Ron Embleton painting shows auxiliaries patrolling the parapet walk.

Hadrian's Wall did not mark the furthest extent of Roman control and influence in Britain.  Several attempts were made to establish Roman control over Scotland, most notably by the great governor and general Agricola ca. AD 82-86 and by the Emperor Septimius Severus and his sons ca. AD 208-211.  Each time, the Romans determined the far north would require more manpower than it was worth to hold permanently and settled instead for a buffer zone of control extending perhaps 50 miles north of the the wall. Several major fortresses, including Newstead, Carpow and Inchtuthil, were built in Scotland and occupied for varying periods. 

Surprisingly, only 15 years after the completion of Hadrian's Wall, the Emperor Antoninus Pius ordered construction of a new wall about 80 miles to the north, along the much shorter Forth-Clyde line.  The Antonine Wall was built by the same three British legions. but this time they used cut turf instead of stone in its construction.  Nineteen forts were built along the wall's 37-mile length, occupied by about 10,000 auxiliary soldiers.  Trouble erupted shortly after the new wall's completion.  Perhaps the Brigantes, Selgovae and other tribes saw the removal of the southern garrison as an opportunity for revolt.  Several years of tough fighting in the AD 150s, plus reinforcements from Germany, eventually restored the situation, but the next emperor, Marcus Aurelius, decided the Antonine Wall was less viable than its predecessor and ordered its abandonment.  Around AD 163,  soldiers evacuated the Antonine Wall, demolishing or burning the milecastles behind them, and reoccupied Hadrian's Wall.

A peaceful frontier still proved difficult to achieve, however.  The wall garrison came under serious attack ca. AD 180 and again in AD 196-197, when Clodius Albinus apparently removed some of the wall garrison to take part in his unsuccessful bid for the throne.  Septimius Severus undertook so much reconstruction ca. AD 200-211 that later generations came to think that he, not Hadrian, had built the wall in the first place.  But the Severan campaigns of AD 208-211 so weakened the northern tribes that the wall came under no further major attack for another 70-80 years, the first sustained period of peace northern Britain had enjoyed since the Roman conquest.  For the further history of wall and Roman Britain, see the Legio VI History page.

Sources: Roman Britain: Outpost of the Empire by H.H. Scullard (Thames and Hudson, 1979); Hadrian's Wall in the Days of the Romans by Ronald Embleton  and Frank Graham (Newcastle, 1984); The Roman Army in Britain by P.A. Holder (B. T. Batsford, 1982).