The first thing to straighten out in approaching Constantin Fasolt's essay is the terminology: what does he mean by canonists and civilians? Canonists are canon lawyers; that is, experts in church law, called canon law. Civilians are experts in civil law. It may make sense at this point to talk a little about the field of law in the period we're studying.
One of the legacies from the ancient world, the Roman world in particular, was Roman law. The Romans in their heyday ruled over a huge territory, and they considered their unique genius to lie in the area of institutions and legal code. The development of a code that would somehow encompass the many people's under Rome's dominions was never fully realized, however; efforts were made in the late empire to pull together the various statutes promulgated by various emperors and governors in various cases. The most famous of these was the Corpus Iuris Civilis or Code of Justinian, who was emperor in the mid-sixth century. The law code fell into two sections, the Institutes and the Digest.
A point of clarification is in order here: since the late third century, the Roman empire was culturally, linguistically, and administratively divided into two sections, the east and the west. The western empire had its capital in what would become Constantinople, spoke mainly Greek, and maintained itself in one form or another until the Ottoman Turks conquered Constantinople in 1453. In 476, Germanic invaders deposed the last of the imperial family of Rome in the west, so in effect, the eastern half of the Roman empire outlasted the west by almost a thousand years. There were still people who called themselves emperors in the west (Charlemagne in the wake of his coronation in 800, and members of the German royal family thereafter), but there was no real continuity with the ancient empire in spite of adoption of the symbolic langauge of continuity.
Justinian in the sixth century, however, saw himself as very much a Roman emperor, and wanted to see the laws of Rome codified--that is, brought together in one document, where conflicts could be resolved and a standard law code published to the entire empire. This document enjoyed a kind of resurgence of interest in the twelfth century, when both the church and various ruling powers felt the need for a legal structure to support the increasing complexities of medieval life. This period saw the development of the power of the papacy, and at the same time royal governments were strengthening themselves in France and England at the expense of the feudal nobility. In Germany and Italy, where royal power was weak, principalities and cities wanted institutional structure of some kind. Italian city-states in in particular developed competency in Roman law to support their diverse commercial and diplomatic activities.
In 1140, a monk from Bologna named Gratian compiled the Decretum, or Concordance of Discordant Canons, which became a foundational document for canon law. The sources were not only Roman law, but Scripture, writings of the Fathers of the church, and decrees of various popes and councils. Around this text there developed an impressive body of commentary, called glosses. Students of canon law could be expected to provide glosses on pieces of the Decretum as part of their education.
Another matter concerning which I need to provide background is the situation in northern Italy and Germany in the 13th century. This region was ruled by the Holy Roman Emperor, a figure who traced his authority loosely to ancient Rome through Charlemagne. He acted as a kind of overlord over a patchwork of jurisdictions, including city-states (these are cities which are themselves states), princely domains, ecclesiastical states (states ruled by bishops rather than lay authorities), and states of all different sizes ruled by noblemen of varying degrees of power and wealth.
The period of the twelfth through the thirteenth century was a period in which the papacy joined together with the city-states of northern Italy to thwart efforts on the part of the emperors to assert their authority in Italy. It was the emperor, in fact, who clashed directly with the papacy during a period of reform in the late eleventh century, called the Gregorian Reform after Pope Gregory VII. The rivalry between the two powers continued into the thirteenth century when Frederick II tried to control Italy. Born in southern Italy, he sought to unite his dominions there (inherited from his mother) with his imperial command in northern Italy. In order to concentrate his efforts on ruling Italy, he made a deal with the German princes under his command that he would allow them to rule almost completely free of interference from him. By the time he died in 1250, it was clear that he had failed in his objective because of the successful alliance between the popes and the Italian cities.
As a consequence, Italy and Germany remained disunified well into the nineteenth century. The papacy won the battle in a sense but lost the war, because by becoming so enmeshed in politics it incurred the wrath of thinking people everywhere (including the poet Dante). Boniface VIII at the beginning of the fourteenth century was treated by the French king with open contempt. It was at that time that the papacy moved out of Rome and took up residence in Avignon, a city between Italy and France. There it stayed until 1378, when the papacy tried to return to Rome and succeeded only in splitting it in two.
This is the background to Constantin Fasolt's fascinating excursion into the questions of legality and legitimacy. What I'd like you to do is try to understand what each of these two terms means, as well as the third term he introduces, that of sovereignty. What do the Bartolists have to say about the relationship between law and legitimacy? What is wrong with that picture? How do Machiavelli and Luther try to resolve it? And how does talk of sovereignty get around the difficulty?