There was a long tradition that there was an important Roman site at Carpow including a villa and bath houses, but the site was lost as it had been burned down and levelled by the Romans on their withdrawal and the remains ploughed away over time. The fortress was first discovered in the early 1940s when parts of the defensive ditches appeared as crop marks, which were visible from the air.  Aerial photography also indicated that on the same site as the fort there were two earlier Roman enclosures, one a probable marching camp from the Agricolan campaign, the other an irregularly shaped enclosure near the Tay, which may have served as a control on a river crossing.  Another related site, also pinpointed by aerial photography, stood on the north bank of the Tay at St Madoes, and was presumably the bridgehead for that side of the river.  The crossing may have been made by a bridge of boats – a coin of Caracalla found at the site depicts such a bridge, and the river would have been just narrow and shallow enough at this point to make this a viable option.

Excavations during the 1960s and 70s focused on the areas of the fort which were most likely to shed light on the site, such as the lines of defences, the gateways and the central buildings.  The fort consisted of a large, roughly square enclosure, which was surrounded by a rampart made of turf and a double ditch, with entrances in the centre of each side.  At the centre of the enclosure were a headquarters building and a praetorium or commanding officer’s house, which, according to the stamped roof tiles, were built by the Sixth Legion Britannica.  As the Sixth Legion only acquired this title in 210 or 211 AD, these buildings can be dated to the period between those dates and the Roman withdrawal c. 212 AD. 

Surrounding the central buildings, and organised around a system of access roads laid out in a grid pattern, were the other buildings, including a granary which had either been built of stone or on stone foundations, and the garrisons’ quarters or barracks, which had been built from timber.  Outside the fort there was a quay on the riverbank, which would have been used for unloading the supply boats. 

Iron bands found along trenches proved to be the remains of the fort’s water supply system – they had been used to join together lengths of wooden water pipe, which had carried water from a spring to the south of the fort into the central buildings and the latrines. The excavation of the south gateway showed up large stone supports for a pair of arches, under which two roads ran. A stone fragment from the gate was found, bearing the head of an eagle.  Another carved commemorative fragment was found at the site of the eastern gate. There was an inscription on this fragment recording a dedication to Caracalla, dating at least this part of the gateway to the very short period between Severus’ death and Caracalla’s withdrawal.  The inscription also records that this part of the fort was built by the Second Legion, Augusta.

Capricorn, the badge of the Second Legion, Augusta

  Both of these stones can now be seen in the McManus Galleries, Dundee.