The sibylline books, though dismissed by J. G. Frazer* as a "convenient farrago of nonsense", were nevertheless one of the most significant influences in the political and religious life of Rome during the Republic. This study has, as its1 objective, a discussion of the history of these books during the Republic between 753 and 12 B. G. It is based, for the most part, on a discussion of all consultations recorded during this period; emphasis is placed on the reasons for consultation, and, in particular, the nature and influence of the sibylline recommendations. Special importance is attached to consultations whose nature and results reveal the sibylline books as a political instrument manipulated by those who controlled them. In addition, there is discussion of any significant innovations ordered by the books, and special attention is paid to any consultations that appear, from the point of view of their results, extraordinary or unusual. A history of the books during this period also necessitates, to a certain extent, a discussion of the religious college that controlled them. It also requires that a certain amount of attention be paid to religious concerns and innovations associated with the books. However, these topics are important to this study only insofar as they have a direct bearing on the republican history of this religious institution. After an introductory discussion of the origin and nature of the sibylline books, their development and history is divided into three periods falling between the years 753--204, 203--83, and 83--12. Each of these periods is discussed from two points of view. Firstly, a normal pattern of sibylline operation is established; secondly, those consultations which do not fit this normal pattern receive more detailed attention. Consultations of a normal nature are grouped, for each period, according to their initiation and result, whereas extraordinary consultations are considered chronologically. It is shown that the sibylline books were a versatile political instrument throughout this period. There is evidence that their manipulation by political groups reached a notable climax during the second Punic War and remained frequent until the end of the Republic. From the point of view of Roman religion, it is seen that the sibylline books were responsible for many important religious innovations, most of which concerned the importation of non-Italic rites and gods into Roman religion. Finally, it is shown that the sibylline tradition, established during the first three centuries of the Republic, declined gradually and steadily between the end of the second Punic War and the second revision of the books, by Augustus, in 12 B. C. This event in particular marked the end of the sibylline tradition at Rome. / Arts, Faculty of / Classical, Near Eastern and Religious Studies, Department of / Graduate