This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
In the contest between the king's courts on the one hand and the local and manorial courts on the other, the king's courts had two great advantages. One of them was the fact that the power of the king was back of the judgments of his courts. It was no longer necessary for a successful litigant to gather in the fruits of the judgment himself. If the defeated party did not comply voluntarily with the judgment of the king's court, the king's official would enforce the judgment for the litigant. The other great advantage that the king's courts had was the fact that theirs was not a tribal law or a law of popular custom, although they probably used tribal custom and popular law as a source of material out of which to build their own jurisprudence. The custom of the king's courts was the custom of the trained jurist. It was the lawyer's law and not the popular law. The result was that in the long contest the king's courts devoured the local and manorial courts and to a large extent it digested its victims. From their own nature and from the limitations upon the jurisdiction of the king's courts, largely self-imposed, the equity and admiralty courts survived with their customs; and to a limited extent the ecclesiastical courts survived. Because of this, ultimately we are likely to think that the law of the king's courts was the standard; and that if the king's courts denied relief in certain cases, it meant that these substantive rights were not recognized at English law. As a matter of fact, the refusal of the king's courts to grant relief depended largely upon jurisdictional questions and did not necessarily mean a denial of the existence of substantive rights. Their refusal to hear many classes of cases is more like the refusal of the courts of the United States to hear cases in which the substantive right is plain, but to which the jurisdiction of the United States courts does not extend.
1 For a later attempt to justify compurgation by a rational but un-historical explanation, see London v. Wood, 12 Mod. 669.
Glanville considers the duel a proper mode of trial in debt in some circumstances: Glanville, Book X, ch. 5.