William of Ockham's (ca. 1288-1347) Opus nonaginta dierum has long been of interest to historians for his theory of rights. Yet the results of this interest has been uneven because most studies do not take sufficient account of the defences of Franciscan poverty already articulated by his fellow Franciscans, Bonagratia of Bergamo, Michael of Cesena, and Francis of Marchia. This book therefore presents and analyzes Ockham's account of property rights alongside those of his confreres. This contextualization of Ockham’s theory corrects many misconceptions about his theory of property, natural law, and natural rights, and therefore also provides a new foundation for studies of his political oeuvre, intellectual development, and significance as a political theorist.