Sir Ronald Syme, whose appreciation of the greatest of Roman historians remains vivid, insightful and compelling more than sixty years after the publication of his monumental work, thus highlighted one of the most challenging and enriching aspects of our own engagement with this author—the simultaneous difficulty and resonance of his language. Any reader will recognise Syme's characterisation of a Latin language bent to Tacitus’ will. Difficult for students, testing for experienced academics, Tacitus’ Latin defies the morphology of the primer and the syntax of the grammar. Everything we learned from Cicero about Latin forms, balanced clauses, rhetorical crescendos and word-order is thrown by Tacitus into disarray. His use of Latin jars and disrupts. Even the call for variatio is subverted, with a conservative and limited vocabulary in play, involving frequent repetition of key abstract terms, but conversely little pattern or regularity in the syntax of sentences. The ‘verbal disharmonies’ both challenge the reader and enrich the meaning. The highly charged nature of Tacitus’ Latin and its capacity, in his ‘possession’, to encapsulate the political complexities of the period is well established. No word is casually or carelessly chosen; phrasing carries resonance; echoes are significant.