• 1 Robert E. Lerner, The Heresy of the Free Spirit in the Later Middle Ages, Berkeley, University o (...)

1A well-worn copy of Robert E. Lerner’s The Heresy of the Free Spirit in the Later Middle Ages has held a central place on my bookshelf for more than half my life. Upon being accepted into the doctoral program at Northwestern University to study medieval history with Robert Lerner in 1996, I rushed to buy and read his best-known work, already a classic even then. I was twenty-six years old, The Heresy of the Free Spirit, published in 1972, was twenty-four1. My immediate impression was that the book’s author possessed a rigorously logical mind, an encyclopedic knowledge of late medieval culture, a flair for incisive prose, and a virtuosic control of the manuscript evidence. More fundamentally, he seemed fearless as he demolished previous scholarly assumptions about the supposed existence of an amoral medieval sect believing itself freed from traditional morality. Robert Lerner’s carefully constructed argument replaced this lurid image with a meticulous study of women and men searching for authentic contact with God; if these late medieval Christians often pushed the boundaries of orthodoxy, they hardly formed an underground sect of Bohemian nihilists. For a fledging doctoral student, Lerner’s larger message was both exhilarating and intimidating: You need not assume that your scholarly predecessors have been right about everything; but if you plan to offer a radical re-interpretation of the sources, you had better be ready to advance a rock-solid reading of the manuscript evidence, capable of withstanding the closest scholarly scrutiny.

• 2 In particular Grundmann’s article “Ketzerverhöre des Spätmittelalters als quellenkritisches Prob (...)
• 3 See Peter Biller, “Goodbye to Waldensianism?”, Past & Present, 192, 2006, p. 3-33; Antonio Senni (...)

2Twenty-seven years later, with the book and I both having passed the half-century mark (well into our later middle ages), it seems safe to say that The Heresy of the Free Spirit has stood up to such scrutiny remarkably well. It certainly remains the standard treatment of its subject. Indeed, in recent years it has become increasingly common to see Lerner’s volume of 1972 cited as a turning point in the study of heresy, insofar as it built on insights from Herbert Grundmann to illuminate the way inquisitors and other churchmen could create the illusion of organized sects by extracting similar sounding answers to standardized and widely distributed lists of questions2. In some cases Robert Lerner might be uneasy about the ends to which his methodology has been put (if there was no organized “heresy of the Free Spirit”, were there any Cathars or even Waldensians?)3, but important innovations will always inspire in ways well beyond their originators’ control. As Jessalynn Bird’s essay in this forum elegantly demonstrates, The Heresy of the Free Spirit in the Later Middle Ages has made its influence felt in many sub-fields of medieval religious history.

• 4 Lerner, Heresy of the Free Spirit, p. 112-119.
• 5 The resulting study is The Beguines of Medieval Świdnica: The Interrogation of the ‘Daughters of (...)
• 6 In addition to the book by Gałuszka and Kras (which includes Letha Böhringer’s essay “The Sweste (...)

5Paweł Kras recounts the pivotal role that The Heresy of the Free Spirit in the Later Middle Ages played in advancing research on the beguines from Świdnica known as the “Hooded Nuns” or “the Daughters of Odelindis”. Although the inquisitorial interrogation of these beguines in 1332 had been published in 1889, it was not until Lerner’s work in 1972 that the original manuscripts were closely re-examined and crucial progress made in understanding this evidence4. Thus when Kras and his co-author Tomasz Gałuszka launched a fresh examination of this important case study around 2014, they self-consciously picked up where Robert Lerner had left off forty-two years earlier, as Kras explains here in fascinating detail5. Their resulting research has given us not only a better understanding of a unique source for beguine life after the Clementine decrees of 1317, but a tantalizing glimpse of a previously overlooked network of sisters who perpetuated the name and ideals of a certain Odelindis, the founder of a community in Cologne6.

• 7 For this manuscript see further J. L. Trombley, A Diabolical Voice: Heresy and the Reception of (...)
• 8 Lerner, Heresy of the Free Spirit, p. 83.

8Finally, Sylvain Piron and Justine Trombley offer a closing blockbuster by arguing that the hostile commentary on the Mirror of Simple Souls found in Padua, Biblioteca universitaria ms. 1647 preserves an expert’s report to the Council of Vienne, and that this report led directly to the infamous decree Ad nostrum (crucial to the contexts studied here by Kras, Simons, and Nieto-Isabel)7. Scholars have long thought that the Mirror, directly or indirectly, must lie behind many of the articles in Ad nostrum. Piron and Trombley now suggest that this hostile assessment of the Mirror probably lies behind all the articles in the decree. The very first article of Ad nostrum turns on the notion of impeccabilitas (using the adjectival form impeccabilis). Piron and Trombley show, first, how this scholastic neologism combined several commonplaces of anti-heretical thought into a generic claim against abstract antinomianism by the early fourteenth century; and, second, how the rigorous refutation of the Mirror in ms. 1647 arrived at employing this term, in spite of the fact that it is never found in the Latin Mirror. That hostile assessment – that the Mirror sinned by claiming that simple souls enjoyed a state of impeccabilitas – then provided the basis for the first article of Ad nostrum, which in turn justified the following seven. Piron and Trombley thus offer a radically new perspective on the origins of Ad nostrum, famously named by Robert Lerner as the “birth certificate” of the heresy of the Free Spirit8.