There are several camps near Birrens at least one of which was first occupied in the
Flavian period from 79 AD onwards probably during the
Agricolan campaigns, when its internal buildings were presumably of timber. Under Hadrian when the frontier was established on
Hadrian's Wall soon after 122, a new fort was constructed as an outpost fort on the site of a late 1st century fortlet with central timber buildings and a large western annexe. The visible fort and its internal buildings date from the
Antonine period around 142 after the reconquest of the
Scottish Lowlands when the earlier fort was rebuilt and enlarged to protect the western road to the
Antonine Wall and to accommodate a nominally 1,000-strong
milliaria equitata garrison of the 1st Cohort Nerviana Germanorum, a mixed unit of cavalry and infantry of the auxiliary army. It was destroyed perhaps by enemy action around 155 and the replacement stone buildings, although of much poorer quality, in the second Antonine period dating to 159 onwards were for the new garrison of the 2nd Cohort of Tungrians, likewise
milliaria equitata. From about 163 it was again an outpost of Hadrian's Wall and was finally abandoned by about 184. The later fort formed the northern terminus of the
Roman-era
Watling Street (using an extended definition of this road), or more simply Route 2 of the
Antonine Itinerary. It was located in the territory of the
Selgovae. ==Finds==