The peoples that overthrew the Roman Empire and ultimately formed modern nations differed by race, country, and language; they resembled one another only in their barbarism. After settling on imperial territory, they clashed with one another for many years, and when the vast confusion at last gave way to stability, they found themselves separated by the very ruins with which they had littered the landscape. Because civilization had been virtually wiped out and public order destroyed, social relations became fraught and perilous, and European society fragmented into a myriad of distinct lesser societies, which lived in hostile isolation. Yet out of this incoherent mass uniform laws suddenly emerged.

The new institutions were not imitations of Roman ones. Indeed, they were so at odds with Roman institutions that Roman law was later used to transform and abolish them. Novel in form, the new laws stood apart from all other legal systems. There was a symmetry to them, and, taken together, they formed a legal system so taut that not even our modern legal codes are more rigorously uniform. Yet these sophisticated laws were intended for use by a semibarbarous society.

How could such legislation have been formulated, propagated, and ultimately established throughout Europe? I do not intend to pursue this question here. What is certain is that in the Middle Ages this system of law could be found in almost every corner of the continent, and in many countries it reigned to the exclusion of all others.