This volume reveals the political, religious, theological, institutional, and mythical ideals that formed the self-identity of the Augustinian Order from Giles of Rome to the emergence of Martin Luther. Based on detailed philological analysis, this interdisciplinary study not only transforms the understanding of Augustine's heritage in the later Middle Ages, but also that of Luther's relationship to his Order. The work offers a new interpretative model of late medieval religious culture that sheds new light on the relationship between late medieval Passion devotion, the increasing demonization of the Jews, and the rise of catechetical literature. It is the first volume of a planned trilogy that seeks to return late medieval Augustinian theology to the historical context of Augustinian religion.