The earliest form of European law is canon law, the first body of legal texts with ambitions to universal applicability for all Christians in the West, regardless of geographic, political or social boundaries. From the fourth century onwards we observe a steady growth in the involvement of individual Christian clerics and church councils in the making and codification of law. Early medieval canon law collections, rulings of church councils, Papal legislation (in the form of letters), and penitential literature, far outnumber the surviving legislation issued by early medieval kings. Canon law, and especially canon law collections, was also much more sophisticated: it drew upon a wide array of sources, it benefited from the debate culture of church councils, it often sought to have a universal rather than local appeal, and it can be seen to interact with various European vernacular laws, some of which are couched in pre-Christian traditions. Canon law is an especially important historical source because the dialectic process through which it was formed allows us to gauge the way in which different contemporary cultural traditions could be fused and eventually forge new identities in the period of transformations from late Antiquity to the early Middle Ages.
However, many of the essential scholarly publications in the field of early medieval canon law are now over a century old. Despite being meticulously researched, they are extremely technical and are all but impenetrable to non-specialists (many are written in Latin). Moreover, many of the sources necessary to study early canon law remain unedited and available only in manuscript. The impenetrability/unavailability of the sources and resources for the study of early canon law led, in the twentieth century, to the subject being generally neglected by early medieval historians. Late antique and early medieval canon law are still considered rather obscure subjects today. Yet, few would argue with the statement that religious and ecclesiastical law was of the highest importance for the literate (mostly clerical) elite throughout the Middle Ages. A better understanding of the dynamics within the genre therefore will not only elucidate the scholarly context of these intellectuals, but the insights gained from the study of these canonical texts can also be brought to bear on the development of western thought more generally.