Western Legal Collections in the Twelfth and Thirteenth Centuries
Collections of Roman Law
Collections of Roman Law
Law became a discipline in the Latin West during late eleventh and early twelfth centuries. The foundations of this “Renaissance of Law” was Justinian’s codification of Roman law in the sixth century. The recovery of Justinian’s legislation was, however, a slow and challenging task. The only part that seems to have survived intact in the West was his Institutes. The other sections, the Digest, the Codex, and Justinian’s later legislation, the Novellae, seem to have circulated in pieces or as abbreviations. The first task that confronted the first teachers of law at the end of the eleventh century was the reconstruction of the complete texts and render translations of those sections that were in Greek. The result was a medieval construct of Justinian’s codification that resembled but differed from the original.
The medieval Digest and Codex, as their forerunners in Justinian’s codification, were divided into books, the books then subdivide into titles and each title contains subchapters of excerpts of the Roman jurisconsults (Digest) or laws (Codex). The medieval Corpus iuris civilis was known as the Littera Bononensis. Since the Digest was not recovered in one piece, the early teachers of law, called glossators because they “glossed” their texts, divided the Digest into three sections: Digestum vetus, corresponding to Book one, title one, law one to Book 24, title two (in modern citation Dig. 1.1.1 to Dig. 24.2), Infortiatum, Dig. 24.3 to 38.17, Digestum novum, Dig. 39.1 to 50.17. The Codex was separated into two parts, books 1 through 9 and books 10 to 12. The other important difference between the medieval and classical text was that the Novellae were ordered very differently from Justinian’s arrangement. The various titles were placed in nine “collationes” and the entire work was called the Authenticum. The abbreviated texts of Justinian’s legislation that were added to the margins of the Codex were called “authenticae.” Perhaps the jurists’ most important work in the dawn of western jurisprudence was to integrate texts of Justinian’s legislation into the margins of the Codex. The final medieval version of Justinian’s codification was not finished until ca. 1120, but additional texts continued to be added until the fifteenth century. From the late eleventh century the books of Justinian’s codification became the libri legales that were taught in the schools and used in the courts of continental Europe.
Several points should be emphasized. The beginnings of western jurisprudence was based on the authority of ancient and Byzantine Roman legal texts. Justinian’s codification was a “Christianized” Roman law which enhanced its authority. Its Christian heritage was an important factor in its acceptance. The first known teachers of law, Pepo and Irnerius, began to teach the texts in Bologna without any mandate from secular or ecclesiastical rulers. The response of students was swift and remarkable. Bologna very quickly became the center of European legal studies.
The literature that these texts inspired, more than the texts themselves, was crucial for establishing law as a foundation stone of medieval society. There is no manuscript evidence for Pepo’s teaching, but hundreds of glosses are attributed to Irnerius in early Roman law manuscripts. In the mid-twelfth century, the “four doctors” of Roman law at Bologna, Bulgarus, Martinus, Jacobus and Ugo, glossed and commented on the libri legales, advised emperors, and trained the next generation of jurists. Three of the most important were Johannes Bassianus, Placentinus and Azo. The capstone of this first stage of medieval jurisprudence stimulated by the libri legales was the Ordinary Gloss of Accursius from Florence to the entire body of Roman law that he finished in the middle of the thirteenth century. No other jurist accomplished that mammoth task before or after. The close connection between Roman and canon law, the Ius commune, was already firmly established by the time Accursius entered the law school at Bologna. He mentioned named Azo as “my doctor.” Two very important canonists, Vincentius Hispanus and Sinibaldus Flieschi (Pope Innocent IV) studied with Accursius.
Collections of Canon Law
Collections of Canon Law
In the 1120’s and 1130’s canon law also became an academic discipline. The evolution of canon law was more difficult than Roman law because there were no authoritative texts that could be used in the classroom. Although collections of canon law texts had been compiled from the sixth century on, and a great wave of canonistic activity began at the beginning of the eleventh century with the Decretum of Bishop Burchard of Worms (between 1008 and 1012), none of these private collections was suited for teaching. Since they were private, the canonical collections did not have the imprimatur of Justinian’s codification. Burchard compiled a very large, comprehensive collection of texts and arranged them in twenty books. He seemed to recognize that the Church needed an universal body of law. His massive collection also can be seen as the legal beginnings of the reform movement within the Church.
There was no immediate successor to Burchard’s vision. Most of the canonical collections compiled between 1000-1100 were much more limited in scope. Their main focus was not comprehensive coverage but ecclesiastical reform. Certain areas in Central and Northern Italy, Southern and Central France, Normandy, the Rhineland and England emerged as important centers of canonistic activity but no one region, including Rome, dominated the compilation of texts.
Burchard’s Decretum circulated widely. It was still being cited by canonists in the early thirteenth century. At the end of the eleventh century Bishop Ivo of Chartres imitated Burchard by compiling another comprehensive canonical collection. Ivo’s Decretum, however, did not enjoy the same wide reception as Burchard’s. An abbreviation of Ivo’s Decretum, most likely not compiled by Ivo, the Panormia, did have a much wider circulation but was far from a comprehensive collection of canonical texts.
Whether comprehensive or not, the eleventh-century collections shared a number of common traits. They were all systematic collections, arranged topically. Churchmen no long found chronologically arranged collections useful. The reformers recognized that to achieve their goals meant that they needed compilations of law that provided texts to support their opinions and that emphasized the central role of the pope in the governance of the church. Although historians have debated whether certain collections reflect a papal or an episcopal agenda for church government or whether some collections were vehicles for and products of the reform movement, these questions are difficult to answer. The canonists collected a wide variety of texts from older collections. Most of the collections dealt with many aspects of ecclesiastical life. Some of them were obviously concerned with certain issues: papal authority, monastic discipline, clerical marriage, simony, and others. Most collections, however, reflect their authors’ search for general norms to govern ecclesiastical institutions and to enforce clerical discipline. Historians’ attempts to describe a collection as having a single purpose end up to be misleading and oversimplifications of complex agendas. It should also not be overlooked that all these eleventh century collections were private. The papacy did not yet take any interest in shaping canonical jurisprudence.
Before the twelfth century, canon law existed as a body of norms embedded in the sources. The collections of canon law included conciliar canons, papal decretals, the writings of the church fathers, and to a more limited extent, Roman and secular law. These collections did not contain any jurisprudence because they existed in a world without jurists. There were no jurists to interpret the texts, to place a text into the context of other norms of canon law, and to point out conflicts in the texts written at various times in different places. The evidence for this generalization lies in the margins of the manuscripts of the pre-Gratian collections: they are empty and almost completely lacking any interpretive glosses.
The teaching of canon law began in the early twelfth century. With the teaching of canon law came jurisprudence. Although the evidence is not conclusive. Gratian of Bologna was probably the first person to begin teaching canon law. He chose the city of Bologna to establish his studio, most likely because the city had already become an important center for teaching Roman law. Until recently the only secure fact that we knew about Gratian was that he compiled a collection of canons entitled the Concordia discordantium canonum, later called the Decretum. We also knew that Gratian’s Decretum very quickly became the most important canonical collection of the twelfth century. It later became the foundation stone of the entire canonical tradition and the first book of the Corpus iuris canonici. It was not replaced as a handbook of canon law until the Codex iuris canonici of 1917 was promulgated.
Since the work of Anders Winroth we have learned much more about Gratian. Winroth discovered four manuscripts of Gratian’s collection that predated the vulgate text of the Decretum. Since then another manuscript of an early recension of Gratian has been discovered in the monastic library of St. Gall, Switzerland. Although all five manuscripts must be studied in detail before we fully understand their significance, some conclusions can already be made. The first recension of Gratian’s work was much shorter than the last recension. The differences between the recensions mean that Gratian must have been teaching at Bologna for a significant amount of time before he produced his first recension and that there was a significant period of time between the early and later recensions. Some evidence points to Gratian’s having begun his teaching in the early twelfth century; other evidence points to the 1130’s. In any case, Gratian’s last recension of his work was finished in the late 1130’s or early 1140’s and immediately replaced all earlier collections of canon law in the classroom.
Gratian became the “Father of Canon Law” because the final version of his collection was encyclopedic and because he provided the schools with a superb tool for teaching. His last “edition” of his Decretum was a comprehensive survey of the entire tradition of canon law. He drew upon the canonical sources that had become standard in the canonical tradition and assembled a rich array of texts, about 4000 in all. His sources will never be known with certainty. He drew upon a collection very similar to the Collectio canonum trium librorum and other central Italian collections. He also took much from Alger of Liège’s De misericordia et iustitia in Causa one. Alger’s work did not circulate in Italy, and Gratian’s knowledge and use of Alger’s work may be evidence that Gratian studied at Laon or some other Northern school. Gratian’s sources were variegated. He included genuine and forged papal decretals, local and ecumenical conciliar canons, a rich collection of writings of the writings of the church fathers — more than any other earlier canonical collection, 1200 chapters in all — Roman and law, and many citations taken from the Old and New Testament.
Gratian introduced jurisprudence into canonical thought. His first innovation was to insert his voice into his collection to mingle with those of the Fathers of Nicaea, St. Augustine, and the popes of the first millennium. He did this with dicta in which he discussed the texts in his collection. Alger of Liège’s tract may have provided Gratian with a model for presenting texts and commentary together. Gratian, however, systematically pointed to conflicts within the texts and proposed solutions. His use of the dialectical “distinction” was an emerging methodology in the early twelfth-century schools. His dicta and causae made the Decretum ideal for teaching, and it became the basic text of canon law used in the law schools of Europe for the next five centuries.
In addition to the novelty of his dicta, Gratian created a collection of canon law that was organized differently than any earlier collection. At the core of his collection he constructed 36 cases (causae). In each case he formulated a problem with a series of questions. He then would answer each question by providing the texts of canons that pertained to it. When the text of the canon did not answer the question without interpretation or when two canons seemed in conflict, Gratian provided a solution in his dicta. Gratian’s hypothetical cases were effective teaching tools that were ideally suited to the classroom.
Perhaps the most important parts of his work for the beginnings of European jurisprudence were the first twenty distinctions of the 101 distinctions (distinctiones) of the first section. In these twenty distinctiones he treated the nature of law in all its complexity. Justinian’s codification of Roman law that was being taught in Bologna at the time Gratian was working on his Decretum defined the different types of law but did not create a hierarchy of laws and did not discuss the relationship between the different types of law. Gratian did that in his first twenty distinctions. These twenty distinctions stimulated later canonists to reflect upon law and its sources. Gratian began his Decretum with the sentence: “The human race is ruled by two things, namely, natural law and usages” (Human genus duobus regitur naturali videlicet iure et moribus). The canonists grappled with the concept of natural law and with its place in jurisprudence for centuries. Their struggle resulted in an extraordinary rich jurisprudence on natural law and reflections on its relationship to canon and secular law. A very distinguished historian has written: Gratian’s Decretum was “essentially a theological and political document, preparing the way — and intended to prepare the way — for the practical asserting of the supreme authority of the papacy as lawgiver of Christendom.” This sentence might possibly describe the purpose of Anselm of Lucca (and other canonists of the reform period) but not Gratian’s plan for his work. If Gratian’s goal for the Decretum were to be limited to one idea (a dubious idea) it would be that he wanted to describe the relationship of law to all human beings. Gratian’s purpose is clearly revealed in the first distinctions in which he analyzed the different types of law. Gratian’s other purpose, I would argue his primary purpose, was to create a book for the teaching of canon law.
Although it was not a well-organized text, Gratian’s Decretum quickly became the standard textbook of medieval canon law in the Italian and Transmontane schools. Its flaws were minor. The revisions of his work sometimes introduced confusion and ambiguity, but the canonists were only sometimes dismayed by his conclusions, comments or organization. In the age following Gratian when the study of canon law became a discipline in the schools in Italy, Southern France, and Spain, the jurists began to fashion the first tools to construct a legal system that met the needs of twelfth-century society. Gratian’s Decretum surveyed the entire terrain of canon law, but his book was only an introduction to the law of the past. Although it provided a starting point for providing solutions, it did not answer many contemporary problems directly. The three most pressing areas in which the jurists used the new jurisprudence to transform or to define institutions were procedure, marriage law, penance, and the structure of ecclesiastical government. In the first half century after Gratian, the jurists concentrated on these problems, and their teachings and writings vividly reflect these concerns.
The earliest changes may have been the addition of chapters to Gratian. They were inserted into the text itself or added to the margins. Although the canonists of the twelfth century called them paleae, they did not know from whence the term came. Huguccio conjectured that the word meant “chaff” added to the good grain; other authors thought that the term was derived from the name of Paucapalea, one of the first commentators on the Decretum. He, they surmised, had been responsible for the paleae added to Gratian’s text. Later canonical collections, especially Compilatio prima, also added canons that had been omitted by Gratian from earlier collections.
Many reasons compelled the papacy to take notice of the law school at Bologna. The Church had become much more juridical during the course of the twelfth century. St. Bernard’s famous lament in his letter to Pope Eugenius III (1153) that the papal palace is filled with those who speak of the law of Justinian confirms what we can also detect in papal decretal letters. The new jurisprudence influenced the arengae and the doctrine of decretals. Canonists undoubtedly drafted these letters in the curia. The rush to bring legal disputes to Rome became headlong in the second half of the twelfth century. Litigants pressed the capacity of the curia to handle their numbers. Popes delegated many cases to judges-delegate, but the curia was still overburdened.
Although papal decretal letters surpassed the Decretum as the basic texts for the study and practice of canon law by the beginning of the thirteenth century, Gratian’s Concordia reigned without significant rivals in the schools and the courts from ca. 1140 to 1190. Perhaps the most significant aspect of canon law’s entry into the law schools of Europe was it relationship with Roman law. Gratian incorporated much Roman procedural law into his Decretum. His successors employed the jurisprudence of Roman law to shape and explain canonical institutions. By the second half of the twelfth century, no jurist could be ignorant of either canonical or Roman jurisprudence. Contemporary jurists called this jurisprudence the Ius commune. It was not a set of laws but a construct of principles, concepts and norms that reigned in Europe until the seventeenth century.
The second half of the twelfth century witnessed a transformation of canon law from a discipline based on the explication of Gratian’s Decretum to a legal system based on papal decretals. This sea change in the sources of law demanded a change in the books used to study, teach, and interpret canon law. Bernard of Pavia, also known as Bernardus Balbi, inaugurated the age of the decretalists, those jurists who concentrated on papal decretals in their teaching and writing. He had glossed Gratian’s Decretum during the 1170’s, beginning his career at Bologna in the age of the Decretists. Like his teacher, Huguccio, Bernard followed a “cursus honorum” that became a common pattern for jurists in the thirteenth century. He studied and taught at Bologna, became provost of Pavia in 1187, bishop of Faenza in 1191, where he succeeded Johannes Faventinus to the episcopal seat, and then, in 1198 he became bishop of Pavia. As a canonist Bernard’s importance was that he gave form and organizational principles to the study and teaching of papal decretals that remained standard in the schools for the rest of the Middle Ages and into the early modern period. He compiled a collection of decretals and other texts that Gratian had excluded and called it a Breviarium extravagantium. Every later collection of papal decretals adopted Bernard’s organizational pattern. After the compilation of Compilationes secunda and tertia after ca. 1210, Bernard’s Breviarium was cited as Compilatio prima by the canonists.
Bernard’s Breviarium was a breakthrough for canonistic scholarship. Papal decretals had begun to occupy an ever more important position in canon law since the 1160’s, but the canonists had not yet devised a way to deal with them. Small, unsystematic collections were first compiled and often attached as appendices to Gratian’s Decretum. Gradually larger collections were made, but since they were usually not arranged systematically, they were difficult to use, consult, and impossible to teach.
Bernard compiled his Breviarium between 1189 and 1190, while he was provost of Pavia. The new collection took the school at Bologna by storm. Although, like Gratian’s Decretum, it was a private collection, the canonists immediately used it in their classes and wrote glosses on it. Bernard’s Brevariuum served as an introduction and as a blueprint for a new system of canon law.
In his prologue to the collection, Bernard wrote that “he had compiled ‘decretales extravagantes’ from both new law and old law and organized them under titles.” Bernard was modest. He revolutionized the study of the “ius novum.” Some earlier collections had been arranged according to titles, but none as systematically as Bernard’s. Roman law once again provided the canonists with a model. The titles of Bernard’s collection in books one and two follow the organization of Justinian’s codification. With the structure of his collection Bernard underlined the interdependence of Roman and canon law in the late twelfth century and reminded students of canon law that Roman law was essential for their studies.
Bernard did not imitate Digest by dividing his collection into a large number of books. He divided his compilation into five books, each with a general subject. Later canonists used the mnemonic verse “Iudex, Iudicium, clerus, connubia, crimen (Judge, Court, Clergy, Marriage, and Crime)” to remember the contents of each book. Bernard’s division into five books was used by almost every later collection.
Bernard collected more than recent papal legislation. When he wrote that he had compiled a collection of “extravagantes” he meant all materials that circulated independently of Gratian. He included many canons from ancient councils and synods, a large number of letters of Pope Gregory I, and many letters of pre-Gratian popes. The bulk of his collection, however, consisted of the decretals of Pope Alexander III (1159-1181). Alexander’s legislation had exercised an enormous influence on canon law, and the canonists had recognized his importance. Bernard included three texts of Pope Gregory VIII (1187) and three of Pope Clement III (1187-1191). These decretals, together with the fact that Bernard called himself the provost of Pavia — he held that post until 1191 when he became bishop of Faenza — establish the dates between which Bernard must have put the finishing touches on his collection.
The jurists immediately began to teach Bernard’s Breviarium at Bologna and produced a number of commentaries on it. In Northern Europe they also tinkered with his text by adding decretals to it. Their innovations were not new. Canonists had added material to established collections for centuries. The Pseudo-Isidorian Decretals, Burchard of Worm’s and Ivo of Chartres’s collections, The Collection in 74 Titles, and Gratian’s Decretum had all undergone minor changes in their texts introduced by anonymous jurists. These collections were “collectiones vivantes,” and their texts reflected their use. In Bologna by the end of the twelfth century, perhaps because the jurists’ commentaries on the collections froze them in the form in which they were received, this practice of cheerfully altering canonical texts diminished but did not completely disappear. In Northern Europe, the practice continued until well into the thirteenth century.
In 1209-1210 Pope Innocent III (1198-1216) authenticated Petrus Beneventanus’ collection of his own decretals. This action marked the first time that a pope had endorsed a private canonical collection. The canonists quickly adopted the text in the schools and called it. Compilatio tertia. The papal imprimatur helped to assure its success. A short time later, Johannes Galensis (John of Wales) compiled Compilatio secunda, and, although unaided by papal approval, his collection became a “received text” in the law schools. Their success was probably due as much to their timing as to their editorial skills. The schools and the courts needed certainty. Papal decretals were now providing that certainty.
Pope Innocent III was the first pope to issue a legal collection of his own legislation when he promulgated the canons of the Fourth Lateran Council (November 1215) as a separate collection. They were immediately glossed and taught in the schools. A short later, Johannes Teutonicus compiled a new collection of Innocent’s decretals into which he incorporated the Fourth Lateran conciliar canons. Innocent refused to authenticate the collection, but, undaunted, Johannes provided his collection with an apparatus. In spite of the pope’s disapproval, after the pope’s death (July 1216) Compilatio quarta was accepted by the schools. This was a significant sign that canon law was not yet under the control of Rome. This would change during the course of the thirteenth century.
After 1217 the Studio in Bologna was dominated by one figure, Tancred of Lombardy, often referred to as Tancred of Bologna. Pope Honorius III selected him to compile a collection of his decretals sometime before 1226. By this time Tancred’s stature was so great, and his rivals so few, that it is difficult to imagine whom Honorius might have chosen other than the archdeacon. Honorius chose Tancred and by doing so he also set a precedent. Canonical collections would no longer be the products of initiatives of private jurists; with only a few exceptions popes began to order collections of their decretals. With Compilatio quinta the papacy took control of its law. For the next century decretal collections were “official” compilations, ordered by the papacy, and sent to the law schools. The age of the “private” decretal collection had momentarily passed.
The last major figure in the period before 1234 was the Catalan Dominican, Raymond of Pennafort. He studied at Bologna and then taught law between 1218 and 1221. After his return to Barcelona, he entered the Dominican order in 1222. Pope Gregory IX summoned him to Rome in 1230 and asked him to compile a new codification that would replace all earlier collections of decretals with one volume. We do not know if he worked alone or with other jurists in the curia. In his bull, Rex pacificus, with which Gregory promulgated the new collection in 1234, he called Raymond’s work a Compilatio, but the canonists quickly adopted the name Decretales Gregorii noni. Along with Gratian’s Decretum, it became the most important collection of papal decretals in the schools and in the courts of Europe. It was also known as the Liber extra (The book outside Gratian’s Decretum).
Like the medieval civilians, the canonists who taught and interpreted Gratian’s Decretum and the collections of decretals created an enormous body of literature. At first, in imitation of the Roman law jurists they wrote glosses on their texts but soon graduated to composing summae, more expansive commentaries, on them. They wrote glosses on all the different books of canon law and eventually were recognized as the standard, ordinary glosses in the schools and the courts. From the middle of the thirteenth century, the canonists began to write massive commentaries on the standard decretal collections. Two jurists are particularly important illustrations of this development in the thirteenth century: Pope Innocent IV and Hostiensis.
Pope Innocent IV wrote a detailed and sophisticated commentary on the Decretals of Gregory IX ca. 1245. Every jurist from his immediate contemporaries to Hugo Grotius in the seventeenth century cited his commentary. He probably began writing it long before he became pope and continued revising it up to the time of his death. He also wrote a commentary on his constitutions of the First Council of Lyon and on the additional decretals that were added to the constitutions in 1246 and 1253. The work was widely distributed in manuscripts and printed in a number of editions between 1477 and 1570.
Innocent emphasized papal authority and power in his commentary. His great predecessor, Pope Innocent III, had established the foundations of papal authority within the church and over secular affairs. Innocent IV expanded and refined Innocent III’s legislation in significant ways. He claimed that the pope could choose between two imperial candidates, could depose the emperor (a power he exercised at the First Council of Lyon), and could exercise imperial jurisdiction when the imperial throne was vacant. Although he granted non-Christian princes the right to hold legitimate political power, he tempered that right by asserting that they must permit Christian missionaries to preach in their realms. In his commentary on the bull of deposition that he had promulgated at the First Council of Lyon (Ad apostolicae dignitatis apicem, Liber sextus 2.14.2), Innocent made remarkable claims for papal authority. The pope did not need the council to validate the deposition of the emperor, because only the pope, not the council, has fullness of power. Innocent asserted that Christ had the power and authority to depose or condemn emperors by natural right (ius naturale). He concluded that the pope had the same authority since he held the office of the vicar of Christ. It would be absurd, he argued, if after the death of St. Peter human beings were left without the governance of one person (“regimen unius personae”). Few popes in the Middle Ages made a more powerful argument for the legitimacy and justness of papal monarchy. Few popes, if any, were more learned in canon law.
Hostiensis (Henricus de Segusio) (ca. 1200-1271) was a contemporary of Innocent IV. These two jurists dominated the second half of the thirteenth century. Hostiensis wrote a massive commentary on the Decretals of Gregory IX and on the Decretals of Innocent IV. He also wrote a Summa on the Decretals of Gregory IX. He worked on his commentary over his entire life and finished its final redaction just before his death. His work circulated widely and became a touchstone for all later canonists.
Although the canonists continued to write commentaries on the libri legales during the fourteenth and fifteenth centuries, another literary genre emerged and became important: consilia. The jurists wrote consilia to advise litigants and judges in court cases. We have consilia that date back to the late twelfth and early thirteenth centuries, but they become genre of great significance in the first half of the fourteenth century. The purpose of the consilia was practical: to advise litigants and judges on specific legal issues raised by a particular case. Consilia quickly became a major source of canonical thinking and jurisprudence. The fourteenth and fifteen centuries have been called the “Age of Consilia.” The jurists wrote thousands of consilia, and some jurists earned considerable fees by writing them. Baldus de Ubaldis (†1400) wrote several thousand consilia and reputedly earned a substantial portion of his income from them.
If he had seen the canon law curriculum at the Law School at Bologna ca. 1300, Gratian would have been pleased and surprised. He would have been pleased that his book still occupied a central place in the study of canon law. Every student of law studied the Decretum. He would have been surprised that Dante Aligheri placed him in Paradiso. Not many poets have bestowed honors on jurists. He would not have anticipated the complete triumph of the papal decretal. Gratian understood canon law as being based on many different kinds of authoritative texts. By the end of the thirteenth century, however, the canonists were transfixed by the papal decretal.
Since the early thirteenth century when Pope Honorius III commissioned Tancred of Bologna to compile a collection of his decretals, popes had followed his lead. Pope Boniface VIII (1294-1303) — who was not a jurist admired by Dante — established a committee of canonists to compile a collection of his own decretals, Pope Innocent IV’s decretals, conciliar canons from Lyon I and II, and other papal decretals that had circulated in other private thirteenth-century collections. This collection of canon law was called the Liber Sextus. Although it was divided into five books and organized like every collection since Bernardus Parmensis’ Breviarium, it derived its name from being the sixth book added to the five books of Gregory IX’s Decretals. Boniface promulgated the new collection on 3 March, 1298 and sent it to all the major schools of canon law. Just as Gregory IX wanted his collection to be a comprehensive and exclusive collection of canonical norms from Gratian to 1234, Boniface’s collection was to be the sole witness of papal decretal legislation from 1234 to 1298. The canonists continued to cite decretals that had not been included in the collections but only rarely. The papacy had put its firm stamp on canon law.
During the fourteenth century, two more papal collections appeared. Pope Clement V (1305-1314) ordered a collection of his decretals be compiled that also included the canons of the Council of Vienne (1311-1312). He died before the collection could be properly promulgated. His successor, Pope John XXII (1316-1334), a distinguished jurist, had the collection revised and issued the new collection on 25 October, 1317. In the canonical literature this collection was named the Constitutiones Clementinae.
The Clementinae was the last official collection promulgated by the medieval papacy. There were two more private collections that were accepted by the schools: the Extravagantes Johannis XXII and the Extravagantes communes. The Extravagantes Johannis XXII contained twenty decretals issued by Pope John XXII during his pontificate. The Extravagantes communes evolved later. The collection contained seventy canons from an array of late medieval popes. The schools accepted these collections, and the canonists wrote extensive commentaries on them.
These facts raise a question about Western canon law that is very difficult to answer. Why did the popes stop promulgating decretal collections after 1317 and not consider new papal collection of decretals until the end of the sixteenth century? It seemed as if the papacy had taken control of its legal system between 1226 and 1317. It promulgated its law officially, following the model established long before by the Emperor Justinian. Although the decretal collections were not comprehensive statements of law like Justinian’s, they provided the law schools with fundamental tools for teaching law. During the thirteenth and early fourteenth centuries one might conclude that the popes perceived their legal role and their authority within the Church much as modern governments do when they exercise control of their legal systems within their territorial states. Like modern governments the popes promulgated, shaped, authenticated, and controlled their legal systems. This model ends after 1317. There were no papal collections of canon law until Pope Gregory XIII promulgated a unified Corpus iuris canonici in 1580. Much later Pope Benedict XIV (1740-1758) issued a volume of his decretals and Pope Pius X (1903-1914) published five volumes of his acts in the early twentieth century.
Although a definitive answer cannot be given, several observations can be made. First the question reflects our conception of how legal systems should be structured and not theirs. No medieval or early modern jurist considered any institution (state) to be the sole producer and repository of law. Second, a new type of collection of papal judicial decisions arose in the fourteenth century, the Decisiones Romanae Rotae. It reported the cases of the papal Court of Audience that was known as the Rota. This court began to carry the main case load of the papal curia at the end of the thirteenth century. Scholars have attributed the collection to one of two Englishmen, Thomas Falstaff and William Bateman. Falstaff was an auditor for the Rota in the middle of the fourteenth century. He also worked in the papal court at Avignon. In either case it may not be by chance that an English jurist conceived of collecting the cases of a single court. The English Year Books that contained the reports of the English Royal courts provided a model for the work.
During the thirteenth and fourteenth centuries popes participated less and less in the daily work of the papal court. Whereas early papal decretals contained decisions in which the pope sometimes, if not always, heard the cases, by the fourteenth century papal letters were no longer the primary vehicles for reporting the judicial activity of the papal curia. It was during this time that the judicial office of the curia became known as the Roman Rota. Papal auditors (auditores) commonly heard the cases that were appealed to Rome. When Pope John XXII (1314-1334) promulgated the decretal Ratio iuris (1332) in which he granted auditors ordinary power to hear cases, the pope confirmed a practice that had been in place for more than a century. During the fourteenth century the “Decisiones” or “Conclusiones” of the Rota were gathered together and manuscripts of them circulated widely. These decisions of the Rota became another source of authority within canon law. By the fifteenth century the Sanctae Romanae Rotae Decisiones were published each year. This practice continues until the present day. A consequence of this institutional development was that collections of papal decretals became far less relevant for canon law.
The decretal collections of the thirteenth and early fourteenth century remained the cornerstones of canonical jurisprudence. They were the libri legales that were used in the classrooms and the courtrooms of Europe. In the second half of the sixteenth century, the papacy decided to revise these standard texts of canon law. In 1566 Pope Pius V convened a committee to examine the complicated textual basis of the libri legales, especially the texts in Gratian’s Decretum. These scholars were called the Correctores Romani. The committee was guided in part by one of the most brilliant scholars of the age, the Spaniard, Antonio Agustín. Pope Gregory XIII promulgated a new Corpus iuris canonici based on the careful scholarship of the Correctores Romani 1580. It was printed for the first time in Rome during 1582. Antonio Agustín’s work De emendatione Gratiani is a window into the work of the Correctores. Pope Gregory XIII’s revised and authenticated version of the standard texts of canon law remained in force until the Codex iuris canonici was promulgated in 1917.
The Books of Feudal Law
In the middle of the twelfth century the jurists began to collect texts and gather them together that treated the rights and obligations of lords and vassals who were bound by feudal contracts. By the thirteenth century, these books were used to teach in the law schools. The law regulating the relationships of lords and vassals in the period before about 1000 A.D. was primarily based upon unwritten customary usages. The sources from the period 800–1000 contain terms like lord (dominus), vassal (vassalus), fief (beneficium or feudum) that later jurists would carefully analyze and define. Historians have learned that when they find these words in early medieval sources, they cannot simply assume that the words describe the lord and vassal relationship that is found in later feudal law, in which a lord bestowed a fief upon a vassal in return for military service and the vassal swore homage and fealty to the lord.
In the period from 800 to 1150, the word that described a fief (sometimes, but not always, a piece of land) was generally beneficium. Although the word feudum, from which the English word feudal is derived, is found in early sources, it replaced beneficium as the standard word to describe a fief only during the twelfth and thirteenth centuries. At the same time the law governing the bestowal of fiefs, the rights of lords and vassals, and the complicated property rights of fiefs emerge from unwritten, ill-defined, customary chaos in which rules and principles were fluid. For political relationships the feudal contract had several advantages over a contract in Roman law. The feudal contract could be inherited and broken for political reasons. When a feudal contract passed from one generation to another, the bonds that the contract cemented were renewed in public ceremonies that reminded each party of its obligations and duties.
Law can exist without jurisprudence, but law without jurisprudence is uncertain. Unless there are jurists to interpret the law, the rights of persons cannot be secure. Before about 1100 Europe was a land without jurists and without jurisprudence. In the first half of the twelfth century the study of law in schools began in north central Italy, especially in the city of Bologna. A professional class of jurists began to teach, practice, and participate in the exercise of power in the courts of the nobility and the governmental institutions of the Italian towns. They used Justinian’s codification of the sixth-century Corpus iuris civilis (Collection of civil law) as the text upon which they commented and with which they taught. Gratian produced a book of canon law upon which the jurists based the study of ecclesiastical (canon) law. These books became the standard libri legales (law books) for the study of law, the ius commune, in the schools and for the practice of law in the courts.
There were no books for feudal law. Because secular and ecclesiastical institutions were involved in legal relationships that were feudal, there was a need for written law and a jurisprudence that would provide an interpretive tool to understand it. Monasteries had feudal ties with persons and institutions. Bishops had feudal relationships with men and towns. Towns had feudal contracts with other towns and persons. The nobility had traditional feudal contracts with vassals but also with towns. Feudalism had become much more than a contract that regulated and defined a relationship between a lord and a vassal. Lawyers who studied the new ius commune at Bologna and other schools quickly realized that texts were needed. Mid-twelfth-century jurists began to organize the study of feudal law around a diverse set of texts. The most unusual was the central role that a letter of Fulbert, the bishop of Chartres in the early eleventh century, played in the development of feudal law.
William V, the count of Poitou and duke of Aquitaine, had asked Fulbert for advice about the obligations and duties that a vassal owed to a lord. William had troubled relationships with his vassals. In his reply (ca. 1020) Fulbert wrote a short treatise on feudal relationships that circulated fairly widely. Its future as a fundamental legal text was assured when Bishop Ivo of Chartres (1091–1115/1116) placed it in his canonical collections. Around 1120 Gratian placed it in his Decretum where it became a locus classicus for canonistic discussions of the feudal contract and the relationship of lord and vassal. Fulbert told William that when a vassal took an oath to his lord, six things were understood to be contained in it whether explicitly expressed or not: to keep his lord safe, to protect him from harm, to safeguard his secrets, to preserve the lord’s justice, to prevent damage to his possessions, and not to prevent the lord from carrying out his duties. Fulbert alleged that he got this list from written authorities, but his exact source, if there was one, has never been discovered. For the next four centuries jurists cited Fulbert’s list of obligations and duties as being central to the feudal oath of fealty.
The canonists’ discussion of this text illustrates why feudal law became so important in the later Middle Ages. They applied Fulbert’s principles to the relationship between popes and bishops, between the emperor and the pope, and between bishops and the clerics under them. The greatest canonist of the twelfth century, Huguccio of Pisa, noted that these principles applied to the oath that the emperor and bishops made to the pope and that clerics sometimes made to their bishops. Huguccio and later canonists concluded that if a cleric gave legal assistance to litigants in a law case against the church or bishop to whom he had sworn an oath, he could be deprived of his benefice just as a vassal could be deprived of his fief for the same offense. Principles of feudal law were extended into relationships that had little to do with the traditional bond between a lord and vassal. Canonistic commentaries also seem to have shaped the ethical and moral standards that a vassal had to maintain. Although they certainly drew upon unwritten customary practices, the canonists laid down the rules in their commentaries on Fulbert’s letter that forbade vassals from violating the sanctity of their lords’ women (wives, daughters, and other members of the household) and from injuring their lords’ interests in court by testifying against them.
The basic books of feudal law were formed in the second half of the twelfth century. In the middle of that century Obertus de Orto, a judge in Milan, sent his son Anselm to study law in Bologna . When Anselm reported to his father that no one in Bologna was teaching feudal law, Obertus wrote two letters to his son (that may be rhetorical conceits) in which he described the law of fiefs in the courts of Milan. Those letters became the core of a set of texts for the study of feudal law. Obertus put his letters together with other writings on feudal law, especially from Lombard law, to create the first of three “recensions” of the Libri feudorum (in the manuscripts the book was also named Liber feudorum, Liber usus feudorum, Consuetudines feudorum, and Constitutiones feudorum). The manuscripts of the first two recensions reveal that there was no standard text. Some of them included eleventh- and twelfth-century imperial statutes of the emperors Conrad II, Lothair II, and Frederick I. Manuscripts of the second recension often contained the letter of Fulbert of Chartres and additional imperial statutes. Typical of legal works in the second half of the twelfth century, the jurists and scribes added texts of various types (extravagantes) to this recension. There are almost no two manuscripts that contain exactly the same text. The text’s entry into the schools must have been slow because the jurists did not immediately comment on it. The first jurist to write a commentary on the Libri was Pillius de Medicina, a jurist of Roman law. He wrote his commentary on the second recension around 1200, probably while he was a judge in Modena. He did not comment on all parts of the Libri,leaving the interpretation of Fulbert’s letter to the canonists. This illustrates an important point about feudal law in the twelfth century: its jurisprudence was not the product of one area of law but of the ius commune.
The final or vulgate recension of the Libri feudorum added constitutions of the Emperor Frederick II, the letter of Fulbert, and other texts that had circulated in the twelfth-century manuscripts. Accursius, the most important jurist of Roman law in the thirteenth century, wrote a commentary based on Pilius’s in the 1220s. It may have gone through several recensions, not all by Accursius. Accursius also wrote the Glossa ordinaria on the rest of Roman law at about the same time. His authority and the importance of feudal law combined to give Libri feudorum along with Accursius’s Glossa ordinaria a permanent place in the Ius commune. From the 1230s on, the Libri was included in the standard manuscripts of Roman law that the stationers at the law schools produced for jurists, students, and practitioners. They placed it immediately after the medieval Authenticum (legislation of Justinian). In the fourteenth century Johannes Andreae questioned whether the Libri feudorum had been legitimately included in the libri legales since no public official had mandated its inclusion in the body of law. Johannes presented both sides of the question, but most jurists decided that it was a legitimate text because it had been accepted by custom and the schools.
Canon law continued to contribute to the jurisprudence of feudal law after the twelfth century but did not produce any legislation as central as Fulbert’s letter. Pope Innocent III (1198–1216) touched upon feudal matters in many of his letters, two of which entered the official collections of canon law under the title De feudis. One of these letters shaped feudal law in an important area: the right of a lord to bestow a fief when he had taken an oath not to bestow the fief on someone else. Feudal law in the later Middle Ages found its jurisprudential roots in Roman law, canon law, and in secular legal systems. This cross-fertilization accounts for the vigor of feudal law until the end of the sixteenth century.
The first penetration of feudal law into secular law can be found at the beginning of the thirteenth century. When the commune of Milan published its statutes in 1216, the titles that dealt with feudal law were taken primarily from the Libri feudorum. The statutes contain an oath that a vassal took to his lord: “I swear that I will be henceforward a faithful man and vassal to my lord. I will not lay open to another to [my lord’s] injury what he has entrusted to me in the name of fealty.” When the emperor Frederick II promulgated a law code for the Kingdom of Sicily in 1231, the Constitutions of Melfi, he carefully regulated the succession of fiefs and the rules governing the nobility in bestowing fiefs. The jurists commented on Frederick’s legislation and incorporated it into the jurisprudence of the ius commune. After the early thirteenth century many secular legal codes dealt with feudal customs in their jurisdictions. They acknowledge a wide range of different practices. In Spain the Siete partidas and in France the Établissements de Saint Louis dealt extensively with the customary law of lords and vassals.
Feudal relationships generated legal problems and court cases in the later Middle Ages. The earliest reports of court cases involving feudal disputes and using feudal law date to the late twelfth century, and their numbers proliferate during the thirteenth and fourteenth centuries. As the number of these cases increased, jurists were called upon to write consilia (legal briefs) to solve them. The jurist who best illustrates this development is Baldus (Baldo degli Ubaldi). He had taught for many years in the republican city of Perugia when, in 1390, Gian Galeazzo Visconti called him to the University of Pavia. Baldus became Gian Galeazzo’s court lawyer and devoted much of his time struggling with Visconti’s legal problems and those of his vassals. Gian Galeazzo was attempting to assert feudal rights over his vassals, and to support his lord, Baldus became enmeshed in the intricacies of feudal law. He finished a commentary on the Libri feudorum in 1393. It became the most important exposition of feudal law in the late Middle Ages. Baldus also wrote a number of long consilia in which he tried to give legal justification to the state based on feudal privileges, rights, and obligations that Gian Galeazzo wanted to create. Baldus found it difficult to justify Gian Galeazzo’s claims when they violated deeply embedded norms of feudal law and the ius commune. The result was a series of torturous and convoluted consilia whose composition betrays Baldus’s ambivalence about his task.
Feudal law remained an important part of European jurisprudence until the seventeenth century. Jurists regularly treated feudal problems in their consilia. They also continued to write commentaries on the Libri feudorum. The last two great commentators on feudal law were Johannes Antonius de Sancto Georgio and Mattheus de Afflictis in the sixteenth century, who wrote extensive and widely circulated commentaries on the Libri.
Books of the Ius proprium: Collections of Local Law
The Ius commune was the jurisprudence of the schools and the courts. It served as a set of norms for all of western Europe. The customary law of kingdoms and local communities remained valid law under the umbrella of the Ius commune. Its norms could and did trump those of the Ius commune, but the jurisprudence of the Ius commune more often provided the interpretive framework for fashioning and interpreting local laws, using the terminology of the medieval jurists, the iura propria. The first European monarch to issue a code of laws for his kingdom, King Roger II of Sicily († 1154), is a good illustration of the process through which Roman law shaped local customary law. Rogers’s jurists produced a body of legislation that scholars have dubbed the Assizes of Ariano but which are called “constitutiones” in Roger’s codification. His legislation was important for several reasons: no other secular European prince promulgated such a sophisticated body of laws in the first half of the twelfth century; no other ruler ordered his legislation compiled into a systematically organized collection; his legislation reveals a close connection to the teaching and study of Roman law in Northern Italy; his constitutions may be the earliest example that we have of the nascent Ius commune’s influence on secular law; and, finally the Emperor Frederick II’s commission of jurists incorporated more than half of his legislation into the Constitutions of Frederick II in 1231 (also called The Liber Augustalis or The Constitutions of Melfi in the older literature) that remained the law of the land in Southern Italy until the early nineteenth century. Most importantly, embedded in Frederick’s Constitutions, Roger’s constitutions lived on. His legislation and Frederick’s were glossed and taught in the schools. If one wished to join Charles Homer Haskins in signaling the importance of the Normans in European history, one could do far worse than choosing Norman legislative activity in Sicily as a milestone in European legal history.
Roger’s Constitutions have been described as “not being an organic whole” and as having “imperfections.” This conclusion asks not only the wrong question but also gives an anachronistic answer. Roger’s was not comprehensive like Justinian’s codification, and no twelfth-century jurist would have thought to compile such a code. When Frederick II promulgated his Constitutions a century later, it too was far from comprehensive. Secular codifications would remain disjointed segments of mosaics that only partially pictured the legal systems for which they were designed. Comprehensive codes belong to the modern world and the jurisprudence of Austinian sovereignty. Modern civil law codes do attempt to cover all parts of the legal system, but law in the Middle Ages could be found in many cupboards, not just in the legislative authority of the state. In a society in which customary law still played such an enormous role, in which large areas of the law were in the hands of ecclesiastical courts, and in which whole areas of the law such as procedure and law merchant were not thought of as being within the purview of the legislator, no jurist would ever have attempted to compile a code that incorporated every jot and tittle of the law of the land.
Although they were not taught in the schools, many other kingdoms, principalities, and cities gathered together their legislation and customary laws in the high Middle Ages. The most precocious were the city states of Italy. Genoa, Piacenza, and Pisa promulgated statutes in the first half of the twelfth century. There is manuscript evidence that jurists glossed them and participated in their composition. In the thirteenth century cities in northern Europe followed. Perhaps the most important and sophisticated royal legislation was the Siete partidas, promulgated by Alfonso X of Castile († 1284) for his Kingdom of Castile. Like the Constitutions of Frederick II it had a life span that stretch into the nineteenth century. Nevertheless, like all the other medieval books of law, the Siete, however, was far from being a comprehensive code.
What distinguishes western European law, the Ius commune, and its jurisprudence from other legal systems is its institutional foundations in the law schools. Its authority was not derived from a great legislator, although it contained legislation from a large number of rulers, and its jurisdiction was not enforced by a powerful, universal monarch. The schools had one language, one set of books, one tradition, and one literature. Whether students studied in Bologna, Montpellier, Oxford, or Salamanca, one set of books, one set of interpretive glosses on those books, provided them with a common jurisprudence. This did not mean that Terence’s maxim “quot homines, tot sententiae” was no longer valid in law. What it did mean is that the jurists understood each other’s arguments and the sources and reasoning of contrary opinions perfectly. It may not have brought concord in the schools and the courtrooms, but it did bring a common ground.
 Pennington, “Corpus iuris civilis,” Dictionary of the Middle Ages (New York: 1983) vol. 3, 608-610.
 Charles M. Radding and Antonio Ciaralli, The Corpus iuris civilis in the Middle Ages: Manuscripts and Transmission from the Sixth Century to the Juristic Revival (Brill’s Studies in Intellectual History 147.Leiden-Boston: Brill, 2007); on the stages in which the Digest was recovered, see Wolfgang P. Müller, “The recovery of Justinian's Digest in the Middle Ages”. Bulletin of Medieval Canon Law 20 (1990) 1-29. On the manuscript tradition of the Institutes, see Francesca Macini, Sulle tracce delle istituzioni di Giustiniano nell’alto medioevo: I manoscritti dal VI al XII secolo (Studi e testi 446; Città del Vaticano: Biblioteca Apostolica Vaticana, 2008). Radding and Ciaralli’s book should be read with caution. Their descriptions of the manuscript traditions is good; their conclusions less so, especially their chapter on the Codex.
 Pennington, “The Beginning of Roman Law Jurisprudence and Teaching in the Twelfth Century: The Authenticae,” Rivista internazionale di diritto comune 22 (2012) 35-53.
 On the Libri legales and their role in the law schools, see the chapter of Michael H. Hofflich and Jasonne M. Grabher, ‘The Establishment of Normative Legal Texts: The Beginnings of the Ius commune’, The History of Canon Law in the Classical Period, 1140-1234: From Gratian to the Decretals of Pope Gregory IX, edd. Wilfried Hartmann and Kenneth Pennington (History of Medieval Canon Law; Washington, D.C.: 2008)1-21.
 Hermann Lange, Römisches Recht im Mittelalter, 1: Die Glossatoren (München: C.H. Beck’sche Verlagsbuchhandlung, 1997) and Lange and Maximiliane Kriechbaum, Römisches Recht im Mittelalter, 2: Die Kommentatoren (München: C.H. Beck’sche Verlagsbuchhandlung, 2007) are the best introductions to the literature produced by the medieval civilians (i.e. teachers of Roman law).
 For information about these jurists and many others, now consult Dizionario biografico dei giuristi italiani (XII-XX secolo), edd. Italo Birocchi, Ennio Cortese, Antonello Mattone, Marco Nicola Miletti (2 vols. Bologna: Mulino, 2013); strangely Placentinus is missing from the Dizionario.
 Lange, Römisches Recht 335-351; see also, Horst Heinrich Jakobs, Magna Glossa: Textstufen der legistischen glossa ordinaria (Rechts- und Staatswissenschaftliche Veröffentlichungen der Görres-Gesellschaft 114. Paderborn-München-Wien-Zürich: Ferdinand Schöningh, 2006).
 On the Libri legales and their role in the law schools, see the chapter of Michael H. Hofflich and Jasonne M. Grabher, ‘The Establishment of Normative Legal Texts: The Beginnings of the Ius commune’, The History of Canon Law in the Classical Period, 1140-1234: From Gratian to the Decretals of Pope Gregory IX, edd. Wilfried Hartmann and Kenneth Pennington (History of Medieval Canon Law; Washington, D.C.: 2008)1-21.
 Greta Austin, Shaping Church Law around the Year 1000: The Decretum of Burchard of Worms (Church, Faith,, and Culture in the Medieval West; Farnham-Burlington: Ashgate, 2009).
 Christof Rolker, Canon Law and the Letters of Ivo of Chartres (Cambridge Studies in Medieval Life and Thought, 4th series, 76; Cambridge: Cambridge University Press, 2010.
 For bibliographical information about Gratian and his Decretum, see Pennington, “The Biography of Gratian: The Father of Canon Law,” University of Villanova Law Review 59 (2014) 679-706.
 Robert Kretzschmar, Alger von Lüttichs Traktat “De misericordia et iustitia”: Ein kanonistischer Konkordanzversuch zus der Zeit des Investiturstreits: Untersuchungen und Edition. Quellen und Forschungen zum Recht im Mittelalter, 2. Sigmaringen: Jan Thorbecke Verlag, 1985).
 Atria A. Larson and John Wei have explored the possible connections between Gratian and the northern schools, see e.g. Larson, “The Influence of the School of Laon on Gratian: The Usage of the Glossa ordinaria and Anselmian Sententie in De penitentia (Decretum C.33 q.3),” Mediaeval Studies 72 (2010): 197-244 and Wei, Gratian the Theologian (Studies in Medieval and Early Modern Canon Law 13; Washington D.C.: Catholic University Press of America, 2016).
 Christoph H.F. Meyer, Die Distinktionstechnik in der Kanonistik des 12. Jahrhunderts: Ein Beitrag zur wissenschaftsgeschichte des Hochmittelalters (Mediaevalia lovaniensia, Series 1, Studia 29; Leuven: Leuven University Press, 2000).
 Richard Southern, Scholastic Humanism and the Unification of Europe (Oxford: Blackwell, 1995) 305.
 Atria Larson, Master of Penance: Gratian and the Development of Penitential Thought and Law in the Twelfth Century (Studies in Medieval and Early Modern Canon Law 11; Washington, D.C.: Catholic University Press of America, 2013) is an excellent example how Gratian’s text forged a jurisprudence.
 For an extended discussion of the Ius commune, see Manlio Bellomo, L'Europa del diritto comune (Roma: Il Cigno Galileo Galilei, 1989); also Pennington, “Learned Law, Droit Savant, Gelehrtes Recht: The Tyranny of a Concept,” Rivista internazionale di diritto comune 5 (1994) 197-209 and Syracuse Journal of International Law and Commerce 20 (1994) 205-215.
 The best guide to what follows are the essays in The History of Canon Law in the Classical Period, 1140‑1234: From Gratian to the Decretals of Pope Gregory IX (History of Medieval Canon Law; Washington, D.C.: The Catholic University of America Press, 2008).
 Pennington, “The Making of a Decretal Collection: The Genesis of Compilatio tertia,” Proceedings of the Fifth International Congress of Medieval Canon Law, Salamanca 1976 (Vatican City: Biblioteca Apostolica Vaticana, 1980) 67-92.
 Pennington, “The Fourth Lateran Council, its Legislation, and the Development of Legal Procedure,”
Bulletin of Medieval Canon Law 32 (2015) in press.
 See Alberto Melloni, Innocenzo IV: La concezione e l'esperienzadella cristianità come regimen unius personae (Istituto per le Scienze religiose di Bologna, Testi e ricerche di scienze religiose 4; Genoa: Marietti, 1990).
 Pennington, “Enrico da Susa (cardinale Ostiense),” Dizionario biografico dei giuristi italiani (secc. XII-XX), edd. Italo Birocchi, Ennio Cortese, Antonello Mattone, Marco Nicola Miletti, Dizionario dei giuristi italiani (XII-XX secolo) (2 vols.; Bologna 2013) 1.795-798.
 Pennington, ABaldus de Ubaldis,@ Rivista internazionale di diritto comune 8 (1997) 35-61.
 Peter Weimar, Peter. “Die Handschriften des ‘Liber feudorum’ und seiner Glossen.” Rivista internazionale di diritto comune 1 (1990): 31–98. Gérard Giordanengo, Le droit féodal dans les pays de droit écrit: L’exemple de la Provence et du Dauphiné, XIIe-début XIVe siècle (Rome: École Française, 1988). Also his essays “Epistula Philiberti.” Féodalités et droits savants dans le Midi médiéval (Hampshire, U.K.: Variorum, 1992) and “Consilia feudalia.” Legal Consulting in the Civil Law Tradition, edited by Mario Ascheri, Ingrid Baumgärtner, and Julius Kirshner (Berkeley, Calif.: Robbins Collection, 1999) Giordanengo has done the best work on French feudal law.
 Pennington, “Feudal Oath of Fidelity and Homage,” Law as Profession and Practice in Medieval Europe: Essays in Honor of James A. Brundage, edited by Kenneth Pennington and Melodie Harris Eichbauer (Ashgate 2011) 93-115.
 Armin Wolf, “Die Gesetzgebung der entstehenden Territorialstaaten,” Handbuch der Quellen und Literatur der neueren europäischen Privatrechtsgeschichte: 1. Mittelalter (1100-1500): Die gelehrten Rechte und Die Gesetzgebung (München: C.H. Beck'sche Verlagsbuchhandlung, 1973) 517-565 remains the best survey of the books of the iura propria in Europe with extensive bibliographical references.
 For what follows see Pennington, AThe Birth of the Ius commune: King Roger II=s Legislation,@ Rivista internazionale del diritto comune 17 (2006) 1-40 and “The Constitutiones of King Roger II of Sicily in Vat. lat. 8782,” Rivista internazionale di diritto comune 21 (2010) 35-54.
 The appearance of Wolfgang Stürner’s magnificent edition of the Constitutions has made work on Norman legislation much easier. In his introduction he has dealt with many of the contentious problems surrounding Roger’s and William II’s laws; on the question of the title of Frederick’s Constitutions see Stürner, Die Konstitutionen Friedrichs II. für das Königreich Sizilien (Monumenta Germaniae Historica, Constitutiones et Acta Publica imperatorum et Regum, 2 Supplementum; Hannover 1996) 7-8.
 Norman legislation in England during the twelfth century was not nearly as sophisticated as that of their cousins in the South. Patrick Wormald has written: “<In the eleventh and twelfth centuries> The Italian materials would alone argue the existence of a vigorous legal profession. Leges Henrici and its ilk are confirmation that there was none in England”, The Making of English Law: King Alfred to the Twelfth Century, 1: Legislation and its Limits (Oxford 1999) 470, and more generally pp. 465-483. See Leges Henrici primi, ed. and trans. L.J. Downer (Oxford 1972) 31; see also the remarks of Mario Caravale, “Giustizia e legislazione nelle assise di Ariano,” Alle origini del costituzionalismo Europeo: Le assise di Ariano, 1140-1990 (Ariano Irpino: 1996) 3-20 at 18-20, who emphasizes the point that both Norman kings emphasize their unitary authority over their kingdoms and their administration of justice.
 See Hubert Houben, Roger II of Sicily: A Ruler between East and West (Cambridge Medieval Textbooks. Cambridge: Cambridge University Press, 2002) 142-143.
 See the general remarks of Wolf on legislation and codification in “Gesetzgebung” 552-555; also consult the still classic study of European codification, Sten Gagnér, Studien zur Ideengeschichte der Gesetzgebung (Acta Universitatis Upsaliensis, Studia Iuridica Upsaliensia 1; Stockholm-Uppsala-Göteborg 1960) 288-366.
 Wolf, “Gesetzgebung” 566-586. The Pisan statutes are the most thoroughly studied: ClaudiaStorti Storchi, Intorno ai Costituti pisani della legge e dell’uso (secolo XII): Europa Mediterranea, Quaderni 11. Napoli: Liguori, 1998). Paola Vignoli, I costituti dell legge d dell’uso di Pisa (sec. XII): Edizione critica integrale del testo tràdito del “Codice Yale” (ms Beinecke Library 415): Studio introduttivo e test, con appendici (Fonti per la Storia dell’Italia Medievale, Antiquitates 23. Roma: Istituto Storico Italiano per il Medio Evo, 2003).
 Las Siete Partidas del sabio rey don Alonso el nono (3 vols. Salamanca 1555), an edition containing a gloss that pays much attention to the Ius commune; see also Las Siete Partidas, translated by Samuel Parsons Scott and edited by Robert I. Burns (5 Volumes. The Middle Ages. Philadelphia: University of Pennsylvania Press, 2001) with a helpful introduction.