The Monarchia Controversy provides both the background to the imperial and ecclesiastical machinations that drove Dante Alighieri to begin penning the Monarchia in 1318 and also the subsequent history of the efforts by papal authorities to ban the book after the writer’s death. Dante’s political treatise on the Empire and the Papacy was listed by the Church in the Index Librorum Prohibitorum in 1564, and it was removed only in 1881. Anthony Cassell’s account of the Monarchia’s genesis is both compelling and provoking, especially in the descriptions of the intransigence of Dante’s proponents and antagonists. While earlier scholars have viewed Dante’s treatise as peacefully divorced from its times, Cassell shows that Dante’s pose of calm authority above the fray was at once traditional, forensic, courageous, and hard-won. Cassell examines in close detail Dante’s relations to his patron Can Grande della Scala, Pope John XXII’s attempts to strip Can Grande of his privileges, the pertinent traditions of canon law, the culture of contemporary political and ecclesiastical publicists, the work of formal logicians, and the motives of Dante’s first post-mortem opponent, Friar Guido Vernant. The author traces the treatise’s reception through and beyond the first censorship and public burning that it suffered in Bologna from Cardinal Bertrand du Poujet in 1328, and the failure of Bertrand’s threat to incinerate the writer should his mortal remains be discovered. To document the history, Cassell presents a fresh, annotated translation of the Monarchia, together with the first English versions of Guido Vernani’s refutation of Dante’s Monarchia (1329), and Pope John XXII’s bull Si fraturm of 1316-17, which sparked the crisis.