A history of ecclesiastical criminal law has yet to be written. In this limited space, we will not attempt to accomplish such an ambitious task. Instead, the aim will be to provide a general overview of how medieval ecclesiastical law contributed to the development of public criminal law.

The century between c. 1130 and 1234 was a time of great renewal and transformation in canon law when much of the foundation was laid that would define the legal structure of not only the church but also secular society well into modern times (see Chapter 30). At this time, papal legislation found its stride, in the form of papal decretals and conciliar decrees (notably from the four Lateran councils, 1123–1215). The inhabitants of Europe sought out the pope’s judicial decisions in unprecedented masses, creating a rich body of papal case law. At the same time, legal study grew exponentially at the law schools, particularly in Bologna, where an expanding and often innovative tradition of analysis and commentary, which were also inspired by the recently rediscovered Roman law of the emperor Justinian, brought canon law to new levels of complexity, sophistication, and precision.

In the Middle Ages, the Church was by far the wealthiest institution in the western world. From the end of the fifth century, the greatest part of its property served to maintain the clergy; hence the importance of the subject. The prohibition against alienating ecclesiastical property and the rules about celibacy, which reliably prevented any kind of hereditary claims, meant that each generation had to redistribute the use of this enormous fortune.

The term religio, like many others in the technical vocabulary of the medieval Church, had more than one meaning. Since the early Middle Ages, it had denoted monastic observance, the life lived by the “regular” monk or nun, but it could also be used to refer to a more general dedication of one’s life to God – the latter meaning in no way eclipsing the former. Bishop Jacques de Vitry (d. 1240), for example, employed the term in his defense of beguines: “We do not consider religious only those who renounce the world and go over to a religious life, but we can also call religious all the faithful of Christ who serve the Lord under the one highest and supreme Abbot.” And this usage was not restricted to spiritual directors who saw the merits of a more interiorized form of religious life.

Church councils formed an integral part of medieval canon law, indeed one might say its backbone. Nicaea I in 325 will be our starting point, for, although this council belongs to the early Church, its influence upon medieval canon law was profound. It was first in the list of councils that came to be regarded as ecumenical, that is, as a council of the whole Church. Although ecumenical councils form the main focus of this chapter, attention will also be given to local councils, which played important roles in canonical development.

The history of medieval Church law has been written largely from the perspective of the ius commune. Following in the footsteps of Gratian, modern scholars have focused their attention first and foremost on ecclesiastical law as a learned and universal phenomenon, privileging the development of canonistic doctrine grounded in papal decretals and the statutes of general councils and taught in the emerging schools of the Latin West in the twelfth and thirteenth centuries. Yet, as jurists of the “classical period” themselves recognized, the picture of canon law in the high Middle Ages would be incomplete without a consideration of its production and reproduction at a regional and local level. In provinces, dioceses, and parishes, people might of course have gained an understanding of canonical legislation and jurisprudence from such seminal texts as Gratian’s Decretum, the so-called Quinque compilationes antiquae, and the Liber extra, but one should be careful not to overestimate the impact of these works. Though attested to in an impressive number of manuscripts and of undeniably great influence, their distribution was nonetheless spotty and they were surely not on the shelves of all medieval churchmen, including many of those wielding ecclesiastical jurisdiction.

The abundance of sources, the extremely broad range of subjects dealt with in late medieval canon law, and the still unsatisfactory and heterogeneous state of research suggest that a history of canon law in the late Middle Ages should be organized as a description of the surviving legal collections in chronological order. Such an approach not only provides a reliable foundation for future research, but also reflects the state of legal development that contemporaries had access to and illustrates the many contingencies that shaped the development of the legal books which constituted the official Corpus iuris canonici from 1582 to 1917.

Between the fourth and tenth centuries, across most of western Europe, law, legal institutions, and legal procedures became Christianized, in the sense that Christian rhetorical tropes, ideologies, and existential perspectives infused legal expression and practices. Royal and imperial courts were sites for interweaving secular and ecclesiastical authority, and hence for interweaving secular and ecclesiastical law. Such interweaving found voice in “mixed assemblies,” that is, assemblies in which both higher clergy and secular nobility participated in judicial and legislative processes; documents issued under the name of a king or emperor also show the integration of secular and ecclesiastical law. Law was not exclusively developed and implemented at royal courts and assemblies: complementing governmental efforts to instantiate Christian law, the educated elite took an interest in law, both as a subject for study and as a resource for informing arbitration, prosecution, or defense of rights and privileges. One of the many streams of legal formation was the practice of collecting, compiling, and conserving decrees and judicial opinions that would, in time, constitute the core of the canon law of subsequent centuries.

Decretals, epistolae decretales, are papal letters that have a claim to universal validity and clarify questions of Church law. Already in Late Antiquity, petitioners would submit legal or disciplinary questions to the Roman emperor, who in response would provide authoritative answers in imperial rescripts. Papal decretal law was the product of an analogous procedure. Private parties would ask the pope to adjudicate their disputes, and in response the pope would set forth authoritative answers in decretal letters. The oldest fully preserved papal decretal is by Pope Siricius (384–99). Only with the pontificate of Alexander III (1159–81), however, did the number of decretals skyrocket and, as a result, there take place the further legal development and elaboration of the ius novum. Just two generations after Gratian’s Decretum (c. 1140), papal legislative acts had developed and changed canon law like never before.

The tenth and early eleventh centuries often fall between the cracks of the “Carolingian Renaissance” and the “Gregorian Reform” of the eleventh-century papal reform movements. Yet scholars are now paying closer attention to the “long tenth century,” c. 900–1020/50. This new research has undermined the idea that Church law sank into a dark period. Canon law, in fact, may be more difficult to describe in this time than in later periods, precisely because it took place on a “horizontal” level, with many local users, rather than unified under a “vertical” papal monarch, as it would be later. Church law was pluralistic in many senses. Many people used it: the local priest; abbots and monks; the bishop, both in teaching and in administering episcopal courts; and councils, sometimes with popes and emperors present. The remarkable number of canon law manuscripts from this period attests to the considerable local interest in canon law. Collections of Church law from this period also continued to be copied into the high Middle Ages – which also testifies to the significance of the achievements of this period. Viewed diachronically, Church law in this period built upon Carolingian legislation as well as institutions and structures.

The term “Classical Canon Law” emerges rather late in the historiography.* Apparently of French origin, it appeared in several book titles from the 1930s onwards as “Droit classique de l’Église” (The classic law of the Church). Gabriel Le Bras may take credit for giving the term international recognition through the monumental multi-volume work on the history of law and institutions in the western Church. In the first volume (1955) of this collective work, Le Bras divided the entire development of western canon law into three periods. He assigned the name “l’âge classique” (the classical age) to the middle period, spanning well over 200 years from the time of Gratian’s Decretum (c. 1140) to the outbreak of the Great Western Schism (1378). Hans Erich Feine was clearly influenced by Le Bras when he replaced the previously neutral section title “IV. Periode: Das kanonische Recht” (The canon law) of his influential Kirchliche Rechtsgeschichte in its fourth edition (1964) with “Das klassische kanonische Recht” (The classical canon law).

The survival of a large number of twelfth- through fifteenth-century copies of canon law texts testifies to their great utility to contemporaneous masters and students, lawyers and judges, and ecclesiastics of varying ranks and occupations. In modern times these handwritten witnesses to the generation, study, and application of canon law continue to be carefully studied for their texts and accompanying notes, explanations, and glosses, written between the lines or in the margins of the page. Through comparison of divergent commentaries and the tabulation of variant editions of the texts, scholars have been able to trace the chronological development of judicial thought and practice. But this is not the whole story. While there is relatively little documentary evidence about the manner in which early classes of law were organized and taught before the institutionalization of learning in universities, the manuscript pages provide valuable evidence of input to and interaction with the text by master and student. Queries and elucidations transcribed in the margins of early canon law manuscripts, along with indications of cross-references in the same text, embody problems raised and discussed during lectures. Further graphic and pictorial signs mark material to be memorized or utilized in classroom debates.

Most of the medieval canon law dealing with heresy, magic, and superstition is found in CC. 23–26 of Gratian’s Decretum, the so-called causae hereticorum, also in C. 33 q. 1, in book 5 of the Liber extra of Gregory IX, in later decretals and conciliar canons, and in the broad literature of canonist commentaries discussed elsewhere in this volume. In one sense, of course, these offenses belong to criminal law and fall into the categories of criminal legal procedure and of mixed temporal and spiritual jurisdiction. In another sense they constitute unique problems of theology, including demonology, and therefore influenced canon law in perhaps more complex ways than some other topics

The sources of eastern canon law are customarily subdivided by rite or rite families: “rite” indicates the entire theological, liturgical, spiritual, and disciplinary tradition of a large geographic and cultural region. A rite family may consist of several independently organized churches. Ritual matters often explain relationships among different legal traditions and their development.

A genuine canon law of the family developed in the high Middle Ages. It was built on papal decisions in specific cases during the second half of the twelfth century and the first decades of the thirteenth, and their interpretation by professors of law. Academic exposition was crucial in this legal field, more so than in others, since ecclesiastical legislation in the first millennium had taken little or no interest in the family. Church courts were largely forced to innovate, seeking papal verdicts and generating many papal rescripts that required interpretation by the masters. As was their wont, the ecclesiastical judges and the canonists also borrowed many rules from Roman law in order to fill the holes in canon law, which happened to touch only incidentally on certain questions, such as guardianship and adoption, and disregarded others entirely, such as emancipation.

According to a tradition recorded by the second-century Christian writer Hegesippus, the grandsons of Jude, Jesus’ brother, were denounced to the Roman emperor Domitian (81–96) because they, like Jesus himself, were descendants of King David. Fearing a restoration of David’s kingdom, Domitian summoned Jesus’ relatives to his imperial court and interrogated them directly: “Domitian asked them if they were descended from David and they admitted it. Then he asked how much property and money they had, and they replied that they only had 9,000 denarii between them, half belonging to each. And this, they said, was not in the form of cash but the estimated value of only thirty-nine plethra of land, from which they paid taxes and supported themselves from their own labour.” Having seen their calloused hands for himself, Domitian proceeded to question the men about Christ and his kingdom, “its nature, origin, and time of appearance.