In This Article Expand or collapse the "in this article" section Canon Law

  • Introduction
  • Reference Works
  • Resources for Manuscripts
  • Research Institutes and Learned Societies
  • Journals and Series
  • Festschriften
  • Modern Historiography
  • Canon Law and Theology
  • Biographies of Important Canonists
  • Byzantine Greek Canon Law

Medieval Studies Canon Law
Edward Peters, Melodie H. Eichbauer
  • LAST REVIEWED: 06 May 2016
  • LAST MODIFIED: 22 February 2018
  • DOI: 10.1093/obo/9780195396584-0033


Canon law began as sets of norms for the regulation of Christian conduct in the world and the relations of Christians with each other. These were based on principles derived from scripture, the influence of respected teachers such as St. Paul, the decisions of ecclesiastical assemblies called synods or councils, and papal decretals. These norms were called canons, rather than laws. The term canon translates the Greek κανών, meaning a carpenter’s straight-edge and, by extension, a guide or rule. Decretals, or letters, were responses of the pope to questions posed to him regarding Church doctrine. While relevant only to that particular circumstance, papal decretals, over time, came to be regarded as binding for all of Christendom. Church councils sought to standardize doctrine, liturgy, and legal norms by the collective decisions of assembled bishops, but regional ecclesiastical identities endured, particularly in the person of the independent local bishop governing his own church with its own customs, in the increasing distinction between clergy and laity, and in the development of a clerical hierarchy. Regional and local councils, presided over by bishops, could either adapt or repeat canons issued at ecumenical councils depending upon the needs. Collections of canons, always privately compiled—until the Liber Extra Decretalium of Pope Gregory IX (r. 1227–1241) in 1234—and adopted for use by regional churches, were arranged either chronologically according to the assumed dates of their texts or systematically according to topics treated. The Greek Christian church adopted the term nomocanon to designate its canons that were approved by the Byzantine emperor and thereby became νομοι, laws. The Latin Christian church called its laws ius canonicum as a parallel, but not dependent, legal system to the study of Roman law. The shift from collections of texts to a legal science—whereby one went to Bologna or Paris, for example, for the specific purpose of studying law—occurred during the classical period, from shortly before 1140 to 1375, beginning with the almost universal adoption of the work of the canonist Gratian, the Decretum. During this period—frequently referred to as the classical period—the doctrine of papal judicial supremacy emerged, and papal legal decisions became the primary source of canon law. In the law books produced during the classical period, canon law acquired a form and structured that remained in effect in the Roman Catholic Church until 1917–1918. Parts of it were adopted in other Christian confessions from the 16th century.

Reference Works

No encyclopedia or dictionary of canon law exists in English. The French Dictionnaire de droit canonique (Naz, et al. 1924–1965) is somewhat dated in places but still the most comprehensive reference work. To some extent, it can be supplemented by more recent and more wide-ranging reference works, such as Fowler-Magerl 2005, Kéry 1999, and Ferme 2007. Annotated translations of specialized genre texts over long periods are now more readily available, especially Somerville and Brasington 1998, Tanner 1990, and in extensive dictionaries of related subjects. Since canon law is closely associated with the doctrines of theology, the Dictionnaire de théologie catholique (Vacant, et al. 1903–1950) is an important reference tool.

  • Ferme, Brian Edwin. Introduction to the History of the Sources of Canon Law: The Ancient Law up to the Decretum of Gratian. Translated by William J. King. Montreal: Wilson and Lafleur, 2007.

    Ferme’s work is a revision and modernization of the classic work by Alfons M. Stickler, Historia iuris canonici latini, I. Historia fontium, which was the major account of the history of the sources of canon law until the beginning of the classical period in the 12th century. Ferme’s revision and updating make this book a major account of the development of the sources, written within a strong Roman Catholic academic tradition, and it is a valuable companion to Kéry 1999 and Fowler-Magerl 2005.

  • Fowler-Magerl, Linda. Clavis Canonum. Selected Canon Law Collections before 1140: Access with Data Processing. Monumenta Germaniae Historica. Hilfsmittel 21. Hannover, Germany: Hahnsche Buchhandlung, 2005.

    Originally published in 1998 and revised in 2003, this research tool, like Kéry 1999, extends to around 1140 and represents the extraordinary capacity of electronically shared information developed over the past several decades. The Monumenta Germaniae Historica is the oldest historical research institute in Germany, and many of its publications are devoted to the history of canon law, e.g., Hartmann 2008 (cited under The Carolingians to the Age of Reform [9th–11th Centuries]) and Fuhrmann 1972–1973 (cited under The Age of Reform to Gratian [11th–12th Centuries]).

  • Kéry, Lotte. Canonical Collections of the Early Middle Ages (ca. 400–1140). History of Medieval Canon Law. Edited by Wilfried Hartmann and Kenneth Pennington. Washington, DC: Catholic University of America Press, 1999.

    Kéry’s comprehensive work covers the period up to Gratian in the mid-12th century. The book is a catalogue of manuscripts of both chronological and systematic collections of canon law produced for ecclesiastical use. For each collection, Kéry lists (1) the author (where known), (2) date of creation, (3) place, (4) type, (5) printed editions, (6) manuscripts, and (7) bibliography. The work is indispensable for the early history to the classical period.

  • Naz, R., et al., eds. Dictionnaire de droit canonique. 7 vols. Paris: Letouzey et Ané, 1924–1965.

    The DDC, as it is commonly known, is a dictionary of canon law from apostolic times to the mid-20th century, featuring articles by many specialist collaborators. Much of its early material on canon law is now dated, but it is still the primary reference tool for the subject.

  • Somerville, Robert, and Bruce Brasington. Prefaces to Canon Law Books in Latin Christianity: Selected Translations, 500–1245. New Haven, CT: Yale University Press, 1998.

    This work contains translations of key prefaces to canon law collections from the first known papal letter to the mid-13th century. The prefaces often indicate the rationale for the collection, the intentions of its author, and the sources on which it drew. Some works, particularly that of Ivo of Chartres, circulated because of their methodology independently of the collection itself, which Rolker 2010 (cited under The Age of Reform to Gratian [11th–12th Centuries]) has shown.

  • Tanner, Norman P. Decrees of the Ecumenical Councils. 2 vols. Washington, DC: Georgetown University Press, 1990.

    While not a reference work in the traditional sense, Tanner provides a translation of the canons of the major church councils from Nicaea I to Vatican II. The original text is a reproduction of G. Alberigo et al. (eds.), Conciliorum Oecumenicorum Decreta (Bologna: EDB, 2002).

  • Vacant, A., E. Mangenot, and E. Amann, eds. Dictionnaire de théologie catholique. 15 vols. in 23. Paris: Letouzey et Ané, 1903–1950.

    Although its focus is on theology, and much of it is dated, the work offers an exhaustive description of the theology behind canon law. There is much directly pertaining to canon law in this exhaustive work.

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