Banna ( Birdoswald ) Banna , now known as Birdoswald Roman Fort , was a fort , towards the western end of Hadrian ' s Wall , in the Roman province of Britannia . Today the site is occupied by a former farm called Birdoswald . , it is the only site on Hadrian ' s Wall at which significant occupation in the post - Roman period has been proven , and it is subject to a long - term archaeological programme under the directorship of Tony Wilmott . It is one of the best preserved of the 16 fort s along Hadrian ' s Wall . The fort is situated in a commanding position on a triangular spur of land bounded by cliffs to the south and east overlooking a broad meander of the River Irthing in Cumbria . In Roman times , the fort was known as " Banna " ( Latin for " spur " or " tongue " ) , reflecting the geography of the site . Cumbria County Council were responsible for the management of Birdoswald fort from 1984 until the end of 2004 , when English Heritage assumed responsibility . The fort . The fort was occupied by Roman auxiliaries from approximately AD 112 to AD 400 . In this western part of Hadrian ' s Wall , the wall itself was originally built from turf , later replaced with stone . ( Hogan , 2007 ) The stone fort was built some time after the wall , in the usual playing card shape , with gates to the east , west and south . Inside were built the usual stone buildings , a central headquarters building ( " principia " ) , granaries ( " horrea " ) , and barracks . Unusually for an auxiliary fort , it also included an exercise building ( " basilica exercitatoria " ) , perhaps reflecting the difficulties of training soldiers in the exposed site in the north of England . Excavations between 1987 and 1992 showed an unbroken sequence of occupation on the site of the fort granaries , running from the late Roman period until possibly 500AD . The granaries were replaced by two successive large timber halls , reminiscent of others found in many parts of Britain dating to the 5th and 6th centuries . Tony Wilmott ( director of the excavations ) has suggested that , after the end of Roman rule in Britain , the fort served as the power - base for a local warband descended from the late Roman garrison and possibly deriving legitimacy from their ancestors for several generations . Extensive geophysical survey , both magnetometry and earth resistance survey , were conducted by TimeScape Surveys ( Alan Biggins & David Taylor , 1999 & 2004 ) between 1997 - 2001 . These surveys established that the sub - surface remains in the fort were well preserved . The later surveys detected two vici ( civilian settlements ) of different characters on the eastern and western sides of the fort . It was these surveys which enabled Time Team to excavate in 2000 , although substantial areas of the vicus still exist , some has been lost by erosion . The survey by TimeScape also determined the location of a bathhouse in the valley of the River Irthing . An area between the fort and the escarpment was excavated by Channel 4 ' s " Time Team " in January 2000 . The excavation detected signs of an extramural settlement ( " vicus " ) , but the area is liable to erosion and the majority of the vicus could have fallen over the cliffs . The wall . The two mile sector of Hadrian ' s Wall either side of Birdoswald is also of major interest . It is currently the only known sector of Hadrian ' s Wall in which the original turf wall was later replaced by a stone wall on a different line . When the rebuilding took place ( probably in the 130s ) the line of the wall was moved approximately 50 metres further north , to line up with the fort ' s north wall , rather than its east and west gates . The reasons for this change are unclear , although David Woolliscroft ( Woolliscroft , 2001 ) has plausibly suggested that it was the result of changing signalling requirements . At any rate , this remains the only area in which both the walls can be directly compared . Approximately 600 metres east of Birdoswald , at the foot of an escarpment , lies the remains of Willowford bridge . This carried Hadrian ' s Wall across the River Irthing . The westward movement of the river course over the centuries has left the east abutment of the bridge high and dry , while the west abutment has probably been destroyed by erosion . Nevertheless , the much - modified visible remains are highly impressive . Until 1996 , these remains were not directly accessible from the fort , but they can now be reached by a footbridge that was lowered into position by an RAF Chinook helicopter . Maiden Way . The fort at Birdoswald was linked by a Roman road , known as the Maiden Way , to the outpost fort of Bewcastle , seven miles to the north . Signals could be relayed between the two forts by means of two signalling towers . Birdoswald Roman Fort today . Today the fort ' s site is operated by English Heritage as Birdoswald Roman Fort . The visitor centre features displays and reconstructions of the fort , exhibits about life in Roman Britain , the site ' s history through the ages , and archaeological discoveries in the 19th and 20th centuries . Visitors can walk outside along the excavated remains of the fort .