BIRRENS ROMAN FORT
Birrens Roman Fort is located on a major overland route north. Roman forces moved into the area circa-AD 80 and built several temporary camps to accommodate their field army. However, the strategic importance of the site prompted construction of a permanent outpost. The fort was rebuilt in AD 158 and probably remained in use for the rest of the Second Century AD.
Birrens Roman Fort is located on a major overland route through the southern uplands connecting Carlisle with the Clyde valley. This key arterial route, which today is followed by the A74(M) motorway and the western mainline, was also on the main line of advance for Roman forces when they invaded southern Scotland circa-AD 80. Under the command of Gnaeus Julius Agricola, a large field army moved into the area and spent a year campaigning against local tribes. A number of large marching camps, temporary enclosures built to protect a sizeable field army, were established in the immediate area at this time. The site of Birrens Roman Fort was also fortified around this time with a small temporary camp aligned on an east-west axis, possibly a small facility to secure the key nodal site when the army was away from their temporary bases. This site was later replaced by a permanent facility, Birrens Roman Fort, sometime between AD 80 and AD 120.
The fort, which was known as Blatobulgio, was built by the Twentieth Legion (Legio XX Valeria Victrix). It was built upon a natural rise at the confluence of the Mein Water and Middlebie Burn. It was an earth and timber structure partially raised over the early enclosure but aligned on a north-south axis. The layout seems to have been typical of forts of the period and would have had a headquarters building in the centre surrounded by barracks, workshops, granaries and a Commanding Officer's house. The garrison of the fort is believed to have been the First Nervian Cohort of Germans (Cohors I Nerviorum Germanorum Milliaria Equitata), a one thousand strong mixed unit of infantry and cavalry traditionally recruited from western Germany.
The Romans consolidated their occupation along the Tyne-Solway isthmus circa-AD 87 and a few decades later constructed Hadrian's Wall with Birrens Roman Fort being maintained as an outpost to the north. However, in AD 138 the Romans advanced back into Scotland in force and established a new frontier, the Antonine Wall, along the Clyde-Forth isthmus. Most of the garrisons of forts along Hadrian's Wall moved north and Birrens may have been abandoned at this time.
Birrens Roman Fort was rebuilt in AD 158 presumably as a result of the re-activation of the Hadrianic frontier after the abandonment of the Antonine Wall. The upgraded fort was extended to the north and also had an additional annexe extending to the west. The northern side, which was vulnerable due to the rising ground beyond, was protected by no less than four defensive ditches. The garrison at this time is believed to have been the Second Cohort of Tungrians (Cohors Secundae Tungrorum Milliaria Equitata), a one thousand strong mixed unit of infantry and cavalry raised in Belgium. It is not clear how long the fort remained occupied but, to date, no evidence has been found of use beyond the end of the second century AD.
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Birrens Roman Fort consists of the earthwork remains of a mid-second century AD outpost. The southern end has suffered for erosion but otherwise the layout of the fort can be appreciated.
Birrens Roman Forts and Camps. Two large marching camps, temporary fortifications built to protect a sizeable field army, were probably constructed in the AD 80s during the campaigns of Gnaeus Julius Agricola.
Birrens Roman Fort. The fort as seen from the air from the north. The extensive ditch system can be seen in the foreground.
Ditches. The north side of the fort was particularly vulnerable due to the rising ground beyond. No less than four ditches protected this side and the trace of them can still be seen.
North Gate. The fort's North Gate.
Birrens Roman Fort.
Mein Water. The fort was built in close proximity to the Mein Water, a significant waterway offering a fresh water source and a means of resupply via river barge.
Fort Platform. The southern end of the fort platform has suffered from erosion.