"Every true definition of equity must be, to a greater or less extent, a history." Both at its origin and throughout its whole existence Equity Jurisprudence has existed as a system of laws supplemental to the English common law. Bound by the principle that "equity follows the law," the jurisdiction of the latter system has always been limited to cases of a character for which the earlier and more basic system failed to provide.

So long as the common law was in the process of formation, it was capable of being extended to cases not expressly provided for, but which were within the spirit of the existing law. Some discretion existed with the early judges where circumstances arose which called for special applications of the general legal principles. In course of time the decisions of the judges had created a series of precedents which were considered as of almost equally binding authority on succeeding judges as were the acts of the great council. The common law had now become in effect a system of written law. It is to this crystallization of the old common law customs into written decisions that many legal historians assign the evolution of the law into that form which rendered further development impractical, and created the necessity for a new and supplemental system of jurisprudence.

The rigidity of the common law during the thirteenth and fourteenth centuries, however, may be more properly ascribed to a far different cause. To appreciate the origin and development of this new influence in English law requires a brief return to the long contest between the common law and the Roman law which has been described in Section 71. The contest between the Roman law and the English common law was finally over and the English common law remained the victor in the field. The effects upon itself, of the contest, however, still remained; not only had it been modified by the various Roman law principles which had been adopted, but it also had been affected in a diametrically opposite direction. The long and hard fought contests which the people of England had waged for their old English laws had had the natural tendency to enhance greatly their affection for those laws. The English common law had become something sacred; something not to be lightly altered. The result was that the English law became rigid, and ill adapted to meet newly arising conditions. Especially was this true in the field of the adjective law. There existed certain original writs, creating certain forms of relief, and if a person had a case which entitled him to receive one of these writs he could obtain relief; otherwise the law was powerless to aid him. An attempt was made to remedy this state of affairs by the twenty-fourth chapter of the Statute of Westminster II, granting to the clerks in Chancery the power to issue writs "in consimilu casu." A liberal construction of this statute would have done much to remedy existing conditions, but a liberal interpretation was not given to it. The statute created a few new forms of action, such as trespass on the case, assumpsit, etc., and then its influence stopped. The common law soon became as rigid as before and cases frequently arose where the party wronged could obtain no redress under the existing law and modes of procedure.