Galeazzo Gualdo Priorato’s Historia (1656) is not only arguably the first biography of Queen Christina of Sweden (1626‑1689) but it also provides a model for the interpretation of her life that influenced biographers over three centuries. This essay investigates Gualdo’s rhetorical strategies and their connection with Christina’s propagandistic aims. Focus is devoted to the author’s conjoint explanation of her abdication and conversion to Catholicism according to which the first is the result of the second; an interpretation that forgoes other reasons for her renunciation of the throne and that would be largely adopted by later biographers.