2. Origin

The theory of separation of powers may be traced back in the writings of classical and medieval thinkers such as Aristotle (384–322 BC). Aristotle understood the divergence between making law and implementing law, and articulated a crude separation between the legislative and executive branches of the government. For instance, Aristotle in his book (“The Politics”) proclaimed that:

“There are three elements in each constitution in respect of which every serious lawgiver must look for what is advantageous to it; if these are well arranged, the constitution is bound to be well arranged, and the differences in constitutions are bound to correspond to the differences between each of these elements. The three are, first, the deliberative, which discusses everything of common importance; second, the officials; and third, the judicial element.”

Further, Aristotle believed that any single form of government was unstable leading to a permanent cycle of disasters. Apart from Aristotle, Jean Bodin one of the earliest thinkers of the modern period highlighted the importance of separating the executive and judicial powers. But actually it acquired greater significance in eighteenth century when John Locke emphasized

that the executive and legislative powers should be separate for the sake of liberty. As liberty is likely to suffer when the same human being makes the law and execute them.

Of the various theorists who wrote of the need to divide governmental powers among different institutions, Montesquieu work has been the most influential. Montesquieu was an 18th century French social and political philosopher who coined the term "trias politica" or "separation of powers" in his his book, “De l’Esprit des Lois” (i.e. the Spirit of Laws), 1748.It is considered as one of the great works in the history of political theory and jurisprudence, and it inspired the Declaration of the Rights of Man and the Constitution of the United States.

Between 16-18th Centuries, the doctrine of separation of powers occupied an upper hand in the struggle of the bourgeoisie against absolutism and the arbitrary rule of kings (i.e. feudal monarchy). Again, the doctrine was used in a number of countries to justify a compromise

between the bourgeoisie, which had won control over the legislature and judiciary, and the feudal-monarchical circles that had retained executive power. With the establishment of the capitalist system the principle of separation of powers was proclaimed as one of the fundamental principles of bourgeois constitutionalism.