We cannot do better than begin here with Professor Petit-Dutaillis, whose labours on English constitutional history have done so much to complement the great work of Stubbs. He writes: “Thanks to Henry II who, we are told, was capable of legal innovation, and to his advisers who understood the principles of Roman Law and knew its technicalities, the English monarchy was the only lay power in Western Europe to establish a common-law by the beginning of the thirteenth century. In France and Germany local custom still prevailed. The characteristic of royal justice in England was that it held local custom as of little account, and that, through its system of assizes and writs, it established a procedure and a jurisprudence of general application which was, on the whole, favourable to a free middle class and hostile to the seignorial spirit. We might well add ‘hostile to the clerical spirit’; for Henry II sought to limit ecclesiastical jurisdiction and to make certain that criminous clerks were punished. The constitutions of Clarendon formed an important and significant part of his legislation.” It is true that Henry's advisers were nearly all clerics; so that, as Pollock and Maitland note with felicitous irony, “it is by popish clergymen that our Common Law is converted from a rude mass of customs into an articulate system; and when the popish clergymen, yielding at length to the pope's commands, no longer sit as the principal justices of the King's Court, the creative age of our medieval law is over”.