This article uses the depiction of the city in the Agricola 21, a key text of Romanisation, to examine Tacitean imperial politics and the relationship between space and power. Following a growing tradition of reading the Agricola as a geographical as much as a historical text, the article argues for Tacitean ambivalence as fundamental to the Agricola, not in the sense of Tacitus being undecided about empire; ambivalence is not manifest in a dichotomous reading of empire as Romans against barbarians, but in the subject position of Tacitus and his assumed readers and in their relationship to the imperial project. Ambivalence constructs a third space which is not a temporal stage (a transitional moment in the historical process of acculturation, between barbarian and Roman), but foundational: this ambivalence exists in contrast and opposition to the utopian visions of an imperial city that we find in the Agricola, a city which is ‘flat’ or one-dimensional.