Abstract
It was not until the beginning of the 17th century, when the science of international law took shape at the hands of Grotius and his successors, that the theory of the balance of power was formulated as a fundamental principle of diplomacy in the realist theory. According to Cobden, the first instance in which we find the "balance of power" alluded to in a king's speech is on the occasion of the last address of William III . A balance of power exists when there is parity or stability between competing forces. As a term in international law for a "just equilibrium" between the members of the family of nations it expresses the doctrine intended to prevent any one state from becoming sufficiently strong to enforce its will upon the rest.The principle involved in this, as Hume pointed out in his Essay on the Balance of Power, would be as old as history. But during the greater part of the 19th century the series of national upheavals which remodelled the map of Europe obscured the balance of power; Cobden speaks of the balance of power as a "mere chimera" , criticising Lord Brougham and Gentz but failing to examine their arguments with great care.
