Das Konzil von Pavia-Siena 1423-1424. By Walter Brandmuller. [Konziliengeschichte, Reihe A: Darstellungen.] (Paderborn: Ferdinand Schoningh. 2002. Pp.xxiv,371.euro50,20.) According to the decree Frequens of the Council of Constance, an ecumenical council was to be convoked by the pope five years following the end of Constance. Thus Pope Martin V in due time summoned a council to meet at Pavia, where a synod was inaugurated April 23, 1423. An outbreak of plague forced the sparsely-attended Council to move to Siena, where it lasted from july until its dissolution in March, 1424. Most of these months were filled with disputes over administrative matters, as well as divisions among the various nations; and the ambivalence of Pope Martin and his ultimate decision to remain away from the council made it difficult to get anything done. Despite the issuance of decrees on a number of issues, little in the way of reform was accomplished. Since its appearance over thirty years ago, students of medieval conciliarism have been indebted to Walter Brandmuller's monograph on the council. In that first edition, Dr. Brandmuller greatly augmented our knowledge of the Council by drawing upon many hitherto neglected manuscript and archival sources, most notably the writings of the envoy to the council of King Alfonso V of Aragon. Based upon this source and others, Brandmuller portrayed the Council as being at the center of complex maneuvering between the Aragonese king and his claims to the Kingdom of Naples, on the one hand, and Pope Martin V and his allies on the other. Although he made extensive use of the Dominican John of Ragusa's treatment of the Council, Brandmuller cautioned that John's interpretations of what happened at Pavia-Siena, particularly his judgments of the motivations behind the actions of Pope Martin V,must be read with extreme caution as a product of John's radical conciliarist perspective years later at the Council of Basel. Dr. Brandmuller not only offered the most extensive treatment of the Council to date, but provided a follow-up volume of previously unedited sources. While noting in his review that As a diplomatic history of the council his book is unsurpassed and it is not likely to be replaced {Catholic Historical Review, LVII [October, 1971], 501), Professor Brian Tierney and other reviewers questioned the author's emphasis on Pope Martin Vs lack of culpability for the council's failure. This new edition of Brandmuller's work is an expansion of his original volume in the light of three decades of research by himself and others. …