The Sibilla erithea is a thirteenth-century Latin prophetic text ascribed to the Erythrean Sibyl, who supposedly lived during the time of the Trojan war. Through enigmatic animal and number allegory, the sibyl ‘foretells’ a history of Greek/Latin conflicts, including the fall of Constantinople to western forces during the Fourth Crusade; the eventual restoration of the ‘Greek’ empire through an alliance with the (here severely criticised) emperor Frederick ii; and the eventual downfall of the Hohenstaufens in an apocalyptic scenario steeped in Scripture and medieval prophetic lore. The text, in both a long and a short version, was edited by Oswald Holder-Egger in 1890 and 1905 respectively, editions which have provided the basis of all subsequent study.Footnote ¹ Jostmann's book supplements and corrects much of that scholarship, providing new editions of three recensions of the text (here labelled K1, K2 and L2), but not the long version published by Holder-Egger in 1890 (here labelled L1). By means of a thorough survey of the manuscript record (a catalogue appears at pp. 377–495), consideration of the traces of the text in the work of other authors (including a discussion of the prophetic Verba Merlini, with which the Sibilla erithea was frequently associated), and a careful thematic analysis of the prophecy itself, Jostmann gets as close as possible to reconstructing the origins and aims of this puzzling text. First, and most crucially, Jostmann shows conclusively that, contrary to Holder-Egger's assumption, the short version of the Sibilla erithea (K1) preceded the more widely circulated long recension (L1). Furthermore, as several other scholars have also deduced, pace Holder-Egger, both short and long versions were composed before the death of Frederick ii in 1250, namely in the summer of 1241 (short version) and early 1249 (long version). Jostmann also credibly disputes the theory that the prophecy was a reworking of a Greek original, as well as Holder-Egger's initial identification of its author as a Franciscan Joachite. Jostmann instead insists upon the text's close overlap with the interests and programme of the papal curia in the early thirteenth century and with a set of ideas articulated in the writings of Innocent iii. Hypothesising an origin among curial circles and a target audience in Sicily and the south of Italy, Jostmann proposes the names of two likely ‘suspects’ in the text's forgery: Cardinal Rainer of Viterbo and Cardinal Johannes of Toledo. While Jostmann is unable to provide a ‘smoking gun’ definitively linking either of the two to the production of the text, his analysis of the curial origins of the prophecy is plausible. Jostmann's detailed study will be an invaluable resource for students of late medieval prophecy. Interested scholars will still need to keep their copy of Holder-Egger's edition of the long text, however. Those unfamiliar with the Sibilla erithea will find Jostmann's rather detailed argument easier to follow if prefaced by a reading of the edition of the short version at pp. 498–506. All in all, this volume is a learned and welcome addition to a growing body of scholarship on prophecy in the later Middle Ages.