William of Ockham (c. 1285-c. 1387) was the most eminent theologian and philosopher of his day, a Franciscan friar who came to believe that the Avignonese papacy of John XXII had set out to destroy the religious ideal on which his order was based: the complete poverty of Christ and the Apostles. A Short Discourse on Tyrannical Government is an attack on the claims of the medieval Church, specifically the papacy, to universal spiritual and secular power. Written at the time of the emergence of the European nation-states, Ockham's work issued a direct hard-hitting challenge to the claims of limitless papal power. The text is accompanied by a full bibliography, a chronology and an introduction setting his work in its intellectual and historical context.