The 173 letters associated with pope Leo I (440-61) as their author or recipient are an indispensable source for the history of the Christian church in the middle of the fifth century. Given Leo’s importance as a statesman and a theologian, it is shocking that no modern edition of his complete correspondence exists. While some editors tackled portions of this corpus in the twentieth century, scholars still rely primarily on the edition of Leo’s letters produced in 1753-55 by the brothers Giacomo and Pietro Ballerini, which J.-P. Migne reprinted in volume 54 of the Patrologia Latina. The volume under review is propaedeutic to a new edition of the pope’s correspondence. The author offers a detailed survey of the reception history of Leo’s letters based on an in-depth examination of the manuscript evidence for their circulation in the Middle Ages. This is no small task. The pope’s letters survive in dozens of medieval collections and travelled in groups numbering as few as two letters and as many as 104. The reconstruction of the textual transmission of the pope’s complex correspondence is a daunting undertaking, yet it is absolutely necessary for the preparation of a modern critical edition of these important fifth-century sources.
The book comprises seven chapters. Chapter 1 provides an introduction to Leo’s life through the lens of his letters, which allow us to trace the issues and concerns that characterized his papacy. These include the threat of false beliefs like Pelagianism, Manichaeism, and Priscillianism; the pope’s involvement in church councils, especially the Second Council of Ephesus (449), to which he sent his influential treatise on Christology (Ep. 28, the so-called Tome of Leo) that confirmed the two natures of Christ at the expense of the teachings of the Monophysites; and his active role in local and imperial ecclesiastical politics both in the western provinces and around the Mediterranean rim. Other aspects of his career, like his fateful meeting with Attila the Hun in 452, are not mentioned in his correspondence. While many of Leo’s letters addressed the mundane concerns of a busy metropolitan bishop, others dealt with issues that would have a lasting impact on the history of canon law and theology. For instance, the pope articulated a doctrine of apostolic succession and papal primacy against the presumptions of Constantinople, which lacked an apostolic founder, that later defenders of Rome’s prerogatives found convincing and authoritative. Chapter 2 offers a survey of the editions of Leo’s letters and their shortcomings from the first printed edition by Giovanni Bussi (1470) to the modern editions of select letters published since the 1890s. The author concludes that the “chief weakness” of the modern scholarly treatment of these letters is “incompleteness” (p. 89) and argues that a new edition of the entire corpus of the pope’s correspondence is necessary.
Chapters 3-6 offer a diachronic survey of the transmission of Leo’s letters in manuscripts dating from the late fifth century to the end of the Middle Ages. Each of these chapters follows a similar format, in which the author introduces the historical context of the period in question, provides the date and context for the creation of each collection, lists the manuscript witnesses, and painstakingly reconstructs the relationship among them. Chapter 3 treats the evidence for the dissemination of the correspondence attributed to Leo in collections of canon law compiled in the pre-Carolingian period, that is, before the middle of the eighth century. In this period, no fewer than four distinctive “proto-collections” of the pope’s letters pertinent to canon law circulated in Italy and Gaul. There were also regional collections relevant to the concerns of local bishops and kept in their archives. Leo’s correspondence lent authority to the earliest collections of canon law made during the so-called renaissance gélasienne (492-523). The most influential compendium from this period was the Collectio Dionysiana, compiled by the monk Dionysius Exiguus (c. 470-c. 540). This work exerted a tremendous influence on later canonists, including the seventh-century compiler Cresconius, who made a wildly popular anthology of canons (the Concordia canonum) that was intended “to help those judging ecclesiastical cases” (p. 167). As Chapter 4 shows, in this same period Leo’s letters pertaining to the Council of Chalcedon (451) circulated with the official Greek acta, sometimes in Latin, sometimes in Greek translation, and sometimes back-translated from Greek into Latin.
Chapter 5 treats the Carolingian period, which witnessed both a proliferation of manuscripts containing Leo’s letters and an interest in gathering larger collections of this correspondence. While the Collectio Dionysio-Hadriana (compiled by Pope Hadrian and sent to Charlemagne around 774) only contained eight of the pope’s letters, it was very influential and survives in almost 100 manuscripts. Even more successful were the so-called “False Decretals” of Pseudo-Isidore. This ninth-century confection was a “compilation of forgeries, manipulated conciliar canons and decretals, and unmodified canons and decretals” that “represent[s] a major force for the transmission of Leo’s letters and their use in canon law before the Decretum of Gratian in the 1140s” (pp. 319 and 322). Indeed, one of the turning points of the Carolingian period in the history of the reception of Leo’s letters was the rise in popularity of Pseudo-Isidore’s “False Decretals” at the expense of Dionysius Exiguus’ sixth-century compilation. It was also during this period that Leo’s Tome (Ep. 28) began to circulate on its own in collections of homilies.
Chapter 6 charts the transmission of Leo’s correspondence in the later Middle Ages. Interest in the pope’s letters spiked in the eleventh century during the reform movement associated with Pope Gregory VII and retained their currency in the twelfth century, when we see the production of manuscripts devoted solely to his writings. Another resurgence occurred in the fifteenth century, when opponents of the Conciliarist Movement deployed Leo’s authority to argue in favor of papal supremacy. Many of the owners of the twenty-nine manuscripts of the pope’s correspondence produced in this century were participants in the Council of Ferrara-Florence (1438-45), which upheld the papacy as the governing power of the church.
Chapter 7 offers a useful conspectus of the 173 documents that comprise the dossier of letters to and from Pope Leo. For each letter, the author provides the numbers assigned by the Ballerini brothers and by Jaffé’s Regesta Pontificum Romanorum, as well as information on the date and recipient of the missive and a brief summary of its contents. While several letters are marked as “decretals,” the author has demurred from offering a discussion of when and how certain letters of Leo were classified as “decretals” in the medieval tradition. This is an avenue of inquiry worthy of further attention.
This meticulous technical study of the transmission history of Leo’s letters is an essential step in the preparation of a new critical edition of the pope’s influential correspondence. Given the complexity of the material presented here, the book is admirably free of all but the occasional typographical error or internal inconsistency. The contradictory reports that Leo’s letters survive in forty-five collections (p. 23) and fifty-eight collections (p. 92) is a rare slip in a volume that is otherwise very attentive to detail. The author deserves our gratitude for the painstaking labor that undergirds this kind of study. We can only hope that a new edition of Leo’s letters, informed by the scholarship on display on this book, will appear before long.