It was replaced by a stone fort that was abandoned in the 4th or 5th Century. Remains can be seen today. The site is in Yorkshire. Support and backup for the Wall defenses?
Thanks ct. Permanent forts were built to accommodate legions on busy routes, to obviate the need for whipping up a temporary walled camp. The Roman presence in Britain largely consisted of a fairly thin spread of regular legions, with auxiliaries from elsewhere in the Empire (and my favorite example, Sarmatian cavalry) who were even less popular than the Romans themselves. The truth is, Roman Britain was probably a great place to live. By the time the legions were withdrawn for good, the Romanized Celtic populations were already under stress by Saxon invaders, and most lacked any experience with warfare (unlike their ancestors).
In the Near East, the legions were deployed in small forts along the frontier; they had cohort-sized forts (or smaller), and this Ilkley fort was probably garrisoned by a fairly small permanent group.