This article presents the evidence for attributing to the English historian and antiquarian Edmund Bolton (1575-c.1634) an anonymous, unpublished manuscript entitled AVERRVNCI or The Skowrers. Ponderous and new considerations vpon the first six books of the Annals of CORNELIVS TACITVS concerning TIBERIVS CÆSAR (Genoa, Biblioteca Durazzo, Ms. A IV 5). As a summary of work in progress towards a critical edition of, and commentary on, the text, it also introduces the principal issues surrounding the study of the author and his subject: the place of the treatise in the context of his life and work; its connections to the anti-Tacitean movement in Stuart England; and its contributions to the development of source criticism and philological analysis in an age of political controversy. Bolton’s Skowrers provides not only a passionate defense of monarchy but also a carefully argued refutation of Tacitus’ account of Tiberius and the first scholarly and systematic attempt in early modern historiography to rehabilitate the emperor’s reputation.