M. Stuart Madden, Pace University School of Law, has published Paths of Western Law after Justinian at 22 Widener L.J. 757 (2013). Here is the abstract.
This article relates the story of three principal paths of law in Western Europe from the periods preceding the gradual dissolution of the Western Roman Empire following the death of Justinian I in 565 A.D. through and including the several centuries thereafter. The period witnessed an acceleration of the absorption of Roman law into the customary law of the various Germanic groups that occupied and ruled the former Roman territories, and the recitation of such law in the form of new law codes promulgated by three of the major Gothic groupings: the Lombards, the Burgundians, and the Salian Franks.Download the article from SSRN at the link.
In the main, the Germanic rulers were attentive to the need for laws that would suit not only German customary law as had been followed for many centuries, but also the Roman law to which their Roman constituencies, now under Germanic rule, had adhered. Importantly, even such Roman law as would be applied was only a bowdlerized version of Justinian’s contributions, as the Digests and other interpretative parts of the comprehensive Corpus Juris Civilis were somehow lost, only to be recovered some centuries later. Thus, for the first several centuries of Germanic rule, the only remnant of written Roman law available was the blunt-edged summarization contained in the Code of Justinian.
Germanic law was revolutionized by its new application to the governance of stable agricultural communities. The Gothic codes also advanced continental law in many ways that today can be seen as building blocks of emerging western law. Perhaps most significantly, the three law codes studied here demonstrate a preference for resolution of disputes by means of composition (compensation), and included monetary incentives therefore. By such means, the Goths were largely successful in turning their culture away from violent retributive justice towards systems of *758 composition for injury. Further to this end were the adoptions of wergeld as an appropriate compensation for a homicide, and also the widespread use of codified tables of composition to be associated with particularized lesser wrongs. These changes in Germanic law gave an increased likelihood of even-handed administration of justice, and provided also a monetized incentive for the family of a victim to forego mayhem in resolving disputes. As to the incidence of violent justice, many ancient Germanic practices, such as blood feud or trial by boiling water, were tamed or eliminated in the development of new agricultural societies. The Gothic codes also adopted remarkably modern distinctions between intentional and accidental harm, as well as negligence standards that assigned uncannily familiar significance to concepts of duty and proximate cause.
In sum, the law codes of the Lombards, the Burgundians, and the Salian Franks provided a civilizing legal bridge between the fall of the Western Empire and the more westernized law codes that would follow in the later Middle Ages.