Upon Hadrian’s death, Antoninus Pius seems to have taken a prompt decision to reconquer southern Scotland. This has been seen as the desire of an Emperor with limited military experience to achieve an easy military victory, but growing Hadrianic evidence for troubles on the northern frontier suggests that there may equally have been pressing local reasons for such a campaign (Gillam 1958, Jobey 1978). The campaigns were underway by 139/140 and victory celebrated in 142. A network of forts was re-established, augmented by a greater number of fortlets, covering similar ground to that held in the Flavian period, but not extending quite so far to the north. Many forts reused Flavian sites, but others were new foundations (such as at Inveresk) or shifted slightly from their Flavian precursors (e.g. Lyne). The most striking outcome of the campaign was the Antonine Wall, the premier Roman monument in Scotland (see 3.5).
Traditionally the Antonine occupation in Scotland was split by scholars into two phases with a period of unrest in the middle (Antonine I and II). This has been convincingly dismissed by Hodgson (1995), with most of the evidence representing site-specific local variation. There are, however, grounds for suggesting a phase of refortification and consolidation in Dumfriesshire, where various strands of evidence do indicate a period of unrest (Hodgson 2009; Wilson 2003), or certainly increased activity for some reason, as evidenced by a possible increase in the numbers of temporary camps in this area which may be Antonine in date (Jones 2009b), and the relative density of fortlets in the area. It is possible that the much-debated siege works around Burnswark hillfort relate to this phase (see section 4.1).
The occupation and operation of the Antonine Wall required the creation of outpost forts up to the River Tay (at Camelon, Ardoch, Strageath and Bertha). Precisely why they were deemed necessary remains a matter of interpretation, though it may be no coincidence that the installations precisely mirrored those of the first century. It certainly indicates that the Antonine Wall was not the limit of direct Roman occupation and control. The chain of towers (the Gask system) running along the Roman road seem to have been used only in the Flavian period, although dating evidence from them is scarce. The road itself is undated (see 3.8 below). There are suggestions from stray finds that some of the forts, including Dalginross and Cargill, may also have seen later occupation (Woolliscroft 2002b and pers comm); this merits further work but this remains to be resolved and emphasises the potential limitations of the existing picture. Our current knowledge base requires improvement in this area and hypotheses formulation and further testing.
The identification of temporary camps of likely Antonine date has proved even more difficult than those of potentially Flavian or Severan date, so the extent of campaigning remains speculative, though the objective appears to have been more limited (Jones 2009a). No temporary camps north of the Forth-Clyde isthmus have yet been confidently assigned to the Antonine period, but recent work at Innerpeffray West, Perthshire a 63-acre (25-ha) camp previously thought to have been of Severan date (St Joseph 1973), indicated that the probable road was later than the camp (Britannia 39, 2008, 274). This raises the intriguing possibility that these camps may be earlier in date and were possibly used in the Antonine, or even Flavian, period.
There is still disagreement about the nature of the Roman occupation of southern Scotland (and northern England) and whether it was opposed by the local population to the extent of stimulating an uprising or the need to impose a special control. Further study of the destruction deposits as well as the nature of the military occupation is therefore important. The reasons for, and the chronology of, the withdrawal remain a matter for debate (see section 3.5).
Further work at Bertha is required to fully understand its layout and chronology, and a better understanding of the defences at Ardoch is also needed. More work is also required on temporary camps to provide for their independent dating, along with more detailed work at Dalginross and Cargill in order to contextualise the stray finds located there. Continuing investigation and assessment of other northern forts is necessary in order to elucidate the possibility of the existence of later phases. The publication of the excavations carried out at Camelon (see Table 4: major unpublished Roman excavations) would considerably advance knowledge.