Berman: Law and Revolution II

A great book for understanding our laws and political institutions is Harold Berman's Law and Revolution:  The Formation of the Western Legal Tradition.  Here is a nice review, by Victor Muniz-Fraticelli, of Berman's follow-up, Law and Revolution II:  The Impact of the Protestant Reformations on the Western Legal Tradition.  Here is a bit: 

Harold Berman made a significant mark in legal historiography with the first volume of Law and Revolution (hereafter LR1). In it, he challenged the standard periodization of Western history, which held that "modernity" began in the sixteenth century and that it was preceded by a long, undistinguished, and largely undifferentiated "middle age" throughout which not much of consequence occurred (LR1, p. 14). Such periodization reflected the historians' disregard for law "as an independent factor, one of the causes, and not only one of the results, of social, economic, political, intellectual, moral, and religious developments." (LR1, p. 44) To focus on the history of the Western legal tradition, Berman argued, would show that the first modern Western legal system can be traced to the end of the eleventh century. Hildebrand's revolutionary assertion of ecclesiastical independence from imperial authority in 1075 helped establish in the Roman Catholic Church a jurisdiction separate and parallel to the many secular jurisdictions of the day (LR1, p. 107ff). This newfound independence coincided with the discovery of the Emperor Justinian's compilations of the law of the Roman Empire, and their methodical study in European universities. Over the next two centuries, under the influence of Papal authority and scholarly method, the Canon Law of the Roman Catholic Church was systematized and transformed into the first modern legal system (LR1, p. 120-23, 253-54). By the same token, secular authorities were stripped of spiritual power and constrained to the functions of government familiar to us today: "the maintenance of peace and the establishment of justice in [the] realm" (LR1, p. 534). The Western legal tradition was born out of the plurality of jurisdictions—and, in particular, the competition between the ecclesiastical and the secular legal systems—that characterized the later part of the Middle Ages (LR1, pp. 273ff, 531ff).

If LR1 is the tale of the triumph of the Papal Revolution, Law and Revolution II (hereafter LR2) is the tale of its demise. (LR2, p. 39) The Papal Revolution had divided the spiritual jurisdiction from the secular and allowed them both to coexist; the Protestant Reformations abolished the ecclesiastical jurisdiction altogether and put many areas of spiritual law—church liturgy, marriage, schooling, moral discipline, and poor relief—back in secular hands (LR2, p. 179). The result was a dramatic transformation of the Western legal tradition. Some have characterized it as a secularization of spiritual realm, but, as Berman notes, it was simultaneously a spiritualization of the secular (LR2, p. 64).