The Sibylla Tiburtina is a Latin prophecy attributed to a prophetess from classical antiquity. It concludes with an account of the End of History, involving the coming of Antichrist and his battle with a Last World Emperor. Approximately 100 manuscripts written between the mid-11th and the 16th centuries survive which testify to the Tiburtina's immense popularity in the medieval West; as such it is a key text for understanding medieval apocalypticism and occupies an important place in the intellectual history of the Middle Ages. This book not only re-examines the Tiburtina as a vehicle for expressing contemporary political concerns triggered by crises thought to herald the End of the World, but offers a new approach by placing it, for the first time, in the context of medieval traditions which saw Sibylline prophecy as independent, non-Christian evidence of Christ's life and as confirmation of His divinity. As is shown, these traditions had a major impact on the reception of the Tiburtina. The book concludes with a repertory of the manuscripts, together with brief outlines of individual textual traditions as represented in groups of manuscripts, which will constitute a valuable reference source for other scholars.