The first edition and translation of a little-known work of medieval political theory, dedicated to one of the more controversial popes of the Middle Ages. It argues for the papacy's central role in secular and church politics on theological, philosophical and historical grounds. A detailed introduction relates the work to 14th century history.This volume presents the first edition and translation of theDyalogus de potentia summi pontifices, a little known, fragmentary work of fourteenth-century political theory by the Dominican Dondinus of Pavia. Dedicated to the Avignon Pope John XXII (1316-1334), it provides theological, philosophical, and historical justifications for the spiritual and temporal supremacy of the papacy asserted by Boniface VIII inUnam Sanctamof 1302. The dialogue unfolds in a dream vision in which an apologist for papal power and a sceptic argue before a judge. While the text at points characterizes opponents of papal power as heretics and even seems to counsel violence against them, the sceptic in the dialogue is nonetheless characterized as sympathetic, reasonable, and open to persuasion. An extensive introduction by the editor relates theDyalogusto relevant landmarks of intellectual history of the early fourteenth century (such as John XXII's constitutionSi fratrumon the vacant Empire and the subsequent pamphlet war with the imperial claimant Ludwig of Bavaria, or the curial trial of secular university master John of Pouilly over his critique of papally-granted pastoral privileges for mendicant friars). The introduction also provides a precise political context for understanding the work through a reconstruction of the career of the author's patron, Cardinal Luke Fieschi of Genoa, and through a consideration of John XXII's pro-Angevin strategy of pacification, inquisition, and crusade against Ghibelline lords of Northern Italy like the Visconti of Milan. Anapparatus fontiumpoints out parallels in col³á