Tacitus’s Roman audience had little interest in detailed British geography, and the inclusion of unfamiliar place names would not have enlightened them. Moreover, Tacitus was not compiling a travel guide. His readers expected not just information but also entertainment, and the occasional mention of exotic names served to keep them engaged.

In his account of Agricola’s third campaign, Tacitus introduces one such exotic name, describing Agricola ‘ravaging the peoples all the way to the Taus (an estuary)’ (Tac., Agr. 22.1), which is almost certainly the River Tay. Ptolemy, in Greek, mentions an estuary named Tava in a similar location (Ptol., Geog. 2.3.4: Taoua eischysis), and its resemblance to the modern name is striking, though ancient and modern names often differ. It’s possible that Tacitus knew this name from being present with his father-in-law, Agricola, by the Tay, perhaps in his final season as a legionary tribune before his quaestorship in Rome.

The ‘new peoples’ (Tac., Agr. 22.1: novae gentes) Agricola encountered were likely the Dumnonii, whose territory spanned the Forth–Clyde isthmus into Stirlingshire and Perthshire. Despite challenging weather, the Roman army intimidated them into possibly surrendering hostages, as had their southern neighbors.

Campaigning armies typically operated from marching camps, not forts. Two such camps, found in Abernethy (Carey) Temporary Camp and Kincladie Wood Temporary Camp (Dunning ) in Perthshire, are tentatively linked to Agricola’s march to the Tay. These large, roughly square camps, with doubled gateways on their north and south sides, were discovered through aerial photography and subsequent excavations.

Tacitus emphasizes Agricola’s wise selection of fort locations, noting that no fort established by him was lost to enemy assault or abandonment. He ensured a year’s supply of provisions at each, making them resilient to long sieges and safe for winter occupation (Tac., Agr. 22.2–3).

During this campaign, Agricola learned of Emperor Vespasian’s death and the succession of Titus. The new emperor’s policies might have differed from his father’s, as indicated by Agricola’s stalling momentum. Gaius Salvius Liberalis, appointed as legatus iuridicus, joined Agricola during this period. Known for his legal expertise, Liberalis had been commended by Vespasian and retained by Titus. His arrival may have signalled a shift in focus for Agricola, from military to civic duties. However, Tacitus, possibly due to a professional rivalry, does not mention Liberalis in his account.

Cassius Dio’s summary of Agricola’s governorship, preserved by Xiphilinus, concludes with Titus’s 15th imperatorial acclamation in AD 79, suggesting an assumption of Britain’s near-conquest, akin to the premature declaration of ‘Judaea captured’ in AD 71.