Hadrian’s Wall - By the early 2nd century Lugavalium had become established as a prominent stronghold and the 'Stanegate' frontier, which consisted of itself and several other forts spanning east to Corbridge, was proving to be a far more stable frontier against the Picts than those established deeper into Caledonia. In 122AD the province was visited by the Emperor Hadrian who approved a plan to build a stone wall the length of the frontier. With the wall a new fort was built at Carlisle in the modern day Stanwix area of the city north of the river. The fort, Petriana, was the largest along the length of Hadrian's Wall and was eventually completed in stone by around 130AD. Like Lugavalium, which lay within sight, Petriana housed a cavalry regiment, Ala Petriana, which at 1000 strong was the sole regiment of this size on the wall. Hadrian's successor Antoninus abandoned the frontier and attempted to move further north and build a new wall between the Forth and the Clyde. This didn't prove successful however and after 20 years garrisons were returned to Hadrian's wall.
Until 400AD the Roman occupation of Britain saw many fluctuations in importance and at one time it broke off from Rome when Marcus Carausius assumed power of the territory. He was later assassinated and suffered Damnatio Memoriae, one of the few surviving references to him was uncovered in Carlisle. Coins excavated in the area suggest the Romans remained in Carlisle as late as the rule of Emperor Valentinian II from 375 to 392AD.
Source & More Information: Wikipedia,Wikipedia, Carlisle, Cumbria, http://en.wikipedia.org/wiki/Carlisle,_Cumbria