Of the twelve Augustae who lived during the fifty years of the so-called "military anarchy" (235-284 A.D.), Ulpia Severina, wife of the "Illyrian" emperor Aurelian (270-275 AD), is certainly one of the most enigmatic and less known. The book focuses on Ulpia Severina, who, even though never mentioned by name in literary sources, has been studied almost exclusively from the perspective of the numerous coins issued in her name and is the subject of many interesting honorific inscriptions that had not been thoroughly examined or adequately valued until this study. This exceptional situation, represented by the sole presence of Ulpia Severina on the throne of Rome, deserves more attention than it has received. The pages of the university history textbooks dedicated to the reconstruction of a fifty-year phase of Roman-imperial history must be, if not rewritten, at least integrated in order to give the deserved space to this empress and, therefore, to the so-called "interregnum,"which lasted at least two months, between the death of Aurelian and the advent of emperor Tacitus.