Professor Alexander here publishes for the first time the Greek text of the Sibylline prophecy long known in medieval Latin versions. Three Greek versions have been identified, and are collated in this critical edition. The editor goes on to argue the chronology of the original version (now lost), and of the version edited here, which he dates to the early sixth century A.D. He next discusses the content and its historical information. This is a very interesting piece of historical detection, followed up with great acumen and cogency.