Carpow lies on the south bank of the Tay Estuary, just east of its confluence with the Earn. Roman remains were noted here in the eighteenth century, but it was not until 1961-2 that a formal investigation of the site was made. By then aerial photography had revealed a rampart and double ditch enclosing some 12 ha. (30 acres), surrounded by annexes and other enclosures. Excavation confirmed the presence of a major military base dating to the early third century, almost certainly connected with the campaigns of the emperor Severus against the Caledonians and Maeatae between 208 and 211. The fort’s main buildings were solidly constructed of stone, suggesting that permanent occupation had been intended. At the centre stood a massive headquarters building, or principia. On one side of it was a buttressed granary; on the other palatial quarters for the fort’s commander. Both the principia and the commander’s house had been roofed with tiles stamped with the mark of the Sixth Victrix Legion. To its honorific title ‘PF’, standing for ‘Pia Fidelis’ (dutiful and faithful) had been added the letter ‘B’ for ‘Britannica’ – achievers of victory in Britain. Severus and his sons had adopted the same title.
Fragments of sculptured panels and inscriptions were found in the vicinity of two of the gates. One appears to refer to the emperor in the singular. This suggests that the inscription is later than February 212. The explanation is as follows. Up to his death in February 211 Severus was co-emperor with his sons Caracalla and Geta. When Severus died at York the empire passed jointly to them. A year later, however, Caracalla murdered his brother to become sole emperor. The Carpow inscription seems to mention only one emperor, in which case it must post-date Geta’s murder. This casts doubt on contemporary accounts of the campaigns in Scotland, which claim that immediately after Severus’s death Caracalla abandoned the recently-conquered territories. That building work appears to have been going on at Carpow a year or more later throws this claim into question.
Carpow was probably the forward link in a maritime supply chain, which ran from South Shields on the Tyne via Cramond on the Forth. Severus’s strategy appears to have been to support his massive forces in the north entirely by sea, to avoid the need of setting up costly and vulnerable land-lines of communications, as Agricola and Lollius Urbicus had done before. This suggests that Severus’s intention was to punish the northern tribes, but not to occupy their territories permanently. An enclosure surrounding the fort at Carpow may have been a defended beach-head for the initial landings. It overlooks the estuary bank, along which shipping could conveniently have berthed. These facilities would have allowed the build-up of forces needed to launch a crossing of the Tay prior to campaigning in the Caledonian territories beyond. A coin of Caracalla dated to 209 shows an army crossing a bridge of boats, and it has been suggested that such a crossing may have been made at Carpow.
Research By Robert Richmond