In such cases, one last resort, and only one, was left to the party needing relief. The King was still considered as the head of the judicial system of the country, and the fount from which all justice was ultimately derived. It was in his power, if he so desired, to sit as a judge in any of his courts; it was in his power to grant extraordinary relief in special cases. A direct petition to the King was therefore the course pursued by those who could not obtain redress at the common law, either because of the defects of that system, or because of the power and high position of their antagonists. The King, being too busy to deal with these matters himself, referred them to the various high officials of his court, and gradually he began to refer them more and more to his Chancellor, until finally, the Chancellor had jurisdiction in all such cases and petitions began to be addressed to the Chancellor directly, instead of to the King. For nearly three centuries we find equity jurisdiction in what might be called its formulative state. The theory of the equity judges was largely summed up in the equitable maxim: "Equity will not suffer a right to be without a remedy." During this period new classes of cases were constantly taken jurisdiction of, and new methods of relief granted, by the authority of the judges themselves, and without any parliamentary sanction. Finally, near the beginning of the seventeenth century, this formulative period came to an end; a general outline of equity jurisdiction had become established and equity jurisdiction could no longer be extended by the authority of its own judges.

The extraordinary or equitable jurisdiction of the court of Chancery seems to have been permanently established as a distinct system of jurisprudence during the reign of Edward III. This may perhaps be mainly attributed to the writ or ordinance of the twenty-second year of his reign which referred all petitions addressed to him relating to matters which were as "of grace" to the Chancellor or keeper of the privy seal. In spite of this writ, however, questions of this character were still referred at times to the Great Council or the Privy Council. The exclusive jurisdiction of the Chancery court dates from the succeeding reign, in which petitions or bills (as they now began to be called) began to be addressed directly to the Chancellor.