The Roman road between Corbridge and Carlisle, which became known as the Stanegate in the post-Roman period, already existed when Hadrian’s Wall was conceived. With forts at either end and spaced out along it (Vindolanda, Carvoran, Nether Denton, and Old Church), as well as fortlets (Newbrough, Haltwhistle Burn, Throp, and Boothby) and towers (Barcombe Hill, Turret 45A, Birdoswald, Mains Rigg, and Pike Hill) between them, this has been seen by some scholars as a frontier, perhaps a prototype for Hadrian’s Wall, but others disagree. Nevertheless, it has been speculated that the original scheme for the Wall – just milecastles and turrets along the curtain wall – would have required the Stanegate forts to supply troops for the garrison and patrol.
It has been suggested that there were further elements to this system to both the east of Corbridge and West of Carlisle. Forts at Wreckenton and Washing Wells on the eastern side, and Burgh-by-Sands to the west have all been invoked as belonging to this putative early frontier system.