In AD 74/75 the Second Augustan Legion (Legio Secunda Augusta) was moved forward to Caerleon (Isca) during operations to subdue the Silures. Isca, the most westerly fortress in the Roman Empire, was to continue as the base of Legio II Augusta for more than 200 years. The importance of Caerleon cannot be overstressed in the opportunities it offers for the study of legionary fortresses and archaeological (as opposed to antiquarian) work has been on-going in and around Caerleon since 1908. The vast amount of evidence derived from these excavations allows archaeologists to explore in detail the structural development and history of the fortress, its garrison and the wider community.
The construction of the first fortress, mainly from timber, and the provisioning of its garrison would have had a significant impact on the local landscape and its population. However, the Second Augustan Legion had many commitments beyond South Wales and there must have been long periods when the fortress would have been maintained by a caretaker garrison. Indeed, this raises the question why the legion retained its home base at Caerleon when its major area of operation was in northern Britain for much of the second century (when the legion was involved constructing Hadrian’s Wall and the Antonine Wall). Archaeological evidence shows that as early as the late second century, the legion, with detachments serving elsewhere, was depleted on a permanent basis.
By the early fourth century it is believed that the Second Augustan Legion either had left Isca for a new base (possibly the fort at Cardiff), or that a reduced legion would have occupied only part of the original fortress. However, despite the undoubted demolition of some buildings from the late second century onwards, there is evidence for continuity of occupation into the late fourth century. Whether this late occupation is the result of a continued military presence or a civilian presence is an important research question for the future.