Tacitean studies, centred on the work of Tacitus (c. 56 – c. 120 AD) the Ancient Roman historian, constitute an area of scholarship extending beyond the field of history. The work has traditionally been read for its moral instruction, its narrative, and its inimitable prose style; Tacitus has been (and still is) most influential as a political theorist, outside the field of history.^[1] The political lessons taken from his work fall roughly into two camps (as identified by Giuseppe Toffanin): the "red Tacitists", who used him to support republican ideals, and the "black Tacitists", those who read his accounts as a lesson in Machiavellian realpolitik.^[2]

Though his work is the most reliable source for the history of his era, its factual accuracy is occasionally questioned: the Annals are based in part on secondary sources of unknown reliability, and there are some obvious minor mistakes (for instance confusing the two daughters of Mark Antony and Octavia Minor, both named Antonia). The Histories, written from primary documents and personal knowledge of the Flavian period, is thought to be more accurate, though Tacitus's hatred of Domitian seemingly colored its tone and interpretations.