Luther anniversaries have often been the catalysts for new scholarship and perspectives on the Reformer's theology and life. This past anniversary (2017) has followed a similar pattern. Among the many works published for the five hundredth anniversary of the Reformation, Eric Leland Saak's book on Luther and the Reformation of the Later Middle Ages contributes to our understanding of the Reformer in significant ways. Dependent on, though not quite a sequel to, his earlier Highway to Heaven: The Augustinian Platform between Reform and Reformation, 1292–1524 (2002), this book expands upon his excellent work on the early history and thought of the Order of Augustinian Hermits. The main thesis of Saak's Highway to Heaven—namely, that the Augustinians were an important and unique reform movement in the late Middle Ages—is now extended to the context of Luther's early theological development and reform activity. The effect is to give us “Brother Martin,” deeply embedded in his monastic context, attempting to carry out in his own way the goals of the order's catechetical and pastoral reforms.

On the one hand, Saak demonstrates his affiliation with Heiko Oberman and his larger body of work on the significance of the late medieval Augustinerschule for the history of the Reformation. Yet Saak's work exhibits careful, independent research that reveals aspects of Luther and his order that have yet to be appreciated. For example, we are given a detailed account of the spiritual and academic formation program of the Augustinians. In the days before the Western Schism (1378–1417), the program was rigorous, with at least sixteen years of required theological study. However, post-schism, the requirements seemed far less extensive. Luther's training does not even approach the rigor of the old system, studying hardly more than three years before receiving his doctorate. Thus, Saak suggests that even if there were a distinctive Augustinian theological tradition promoted within Luther's order, it is highly unlikely that Luther would have been immersed in it. Rather, Luther's Augustinianism aligns with the late medieval shift away from speculative theology toward a theology of a more practical and pastoral character—i.e., what Berndt Hamm coined Frömmigkeitstheologie.

From this vantage point, Saak attempts to take up a variety of questions about Luther's theological development. He reassesses (rather convincingly) Luther's “tower experience,” both in terms of its date and its content. He also tries to recast (less convincingly) Luther as a moderating Aristotelian rather than exclusively a critic of the philosopher. Other topics are dealt with in a somewhat disjointed fashion. There are close readings of Luther but their contribution to the overall thesis of the book is less clear, appearing more as separate studies that may have found a better reading as articles in a journal. Still, Saak's close attention to detail and his exploration of less-examined texts makes it worth wandering a bit.

All of this, however, serves as precursor to the main argument of the book: namely, that Luther's true breakthrough marked the end (and failure) of one reform effort—the late medieval Augustinian reform—and the beginning of another (also ultimately a failure). This shift was not the insight into some Pauline passage or theological concept like faith or justification. Rather, it was the moment that Luther came to the conclusion that the papacy as such was the Antichrist and the last days had arrived. While Luther would begin to consider such a possibility after his meeting with Cajetan, in 1518, the decisive moment came in February of 1520. With rumor of a papal bull threatening excommunication, Luther came upon two consecutive discoveries. The first was that after having read Jan Hus's De Ecclesia, Luther realized that he shared his understanding of the Gospel with the Bohemian and that the church had condemned it. The second came four days later when he finally read the humanist Lorenzo Valla's definitive refutation of the controversial Donation of Constantine. The whole institution appeared to Luther to be built on lies: “I am so overwhelmingly horrified in the very depths of my being that I can scarcely no longer doubt that the pope is that very Antichrist!” (WABr 2, 49). The effect that this had on Luther's ecclesiology and his overall reform goals cannot be overstated. The world had changed for Luther and the sense of urgency that marked Luther's efforts thereafter forever changed all efforts at reconciliation and comprehensive reform.

Saak's work, in spite of some of the compositional weaknesses mentioned above, is an important contribution to our reading of Luther and those world-changing events that unfolded five hundred years ago. Students and scholars of the Reformation should read his book with pencil in hand.