Arbitration has had a long history in the United Kingdom and the United States. For many centuries, it has been widely used for the settlement of a variety of disputes between states, state entities and private parties and between private parties inter se. In England, the integration of equity and common law proceeded gradually until the beginning of the fifteenth century, when it slowed down and came to a halt. Thereafter, law and equity flowed in separate channels; and for many hundred years, much of the ethical content of English law consisted of principles of equity developed and applied in a separate court. Equity was used to correct the inadequacies and precedent-bound decisions of the common law in jurisdictions including the United States. But the situations in which and principles upon which relief was granted became in the course of time so well defined that equity developed into a technical branch of the law like what it was intended to correct. Reliance on equity to bring about a balance between legal rights and the interests of those persons who would be seriously harmed by their strict enforcement became less frequent, with the result that equitable principles as to what was fair and just were far less widely used in Anglo-American law than in any of the other great legal systems in the world. The simultaneous existence of two systems of substantive law in modern times is a phenomenon peculiar to common law countries. In two competing systems in the same body of law, the concept of ‘equity’ came to be regarded as an act of grace; it could not be demanded as of right.