Niccolò Machiavelli 1469-1527,
In a time where most believed that "Good Moral" leaders were also "Good Political " leaders and ruled with the "Grace" of God, Machiavelli wrote a divergence view of the power of a leader and the State. In his most famous work The Prince (Il Principe), he made the case that power, not the moral character, defines political action. To be an effective leader, one must understand the proper use of power and its application to the control of and success of the State. Individuals of the State must be brought to obey this power thereby maintaining the success and security of the State and all its citizens. In Machiavelli's eyes a leader that is respected (or even feared) for his power will be more successful than one who is admired for his "Goodness."
The Prince puts forth the belief that the goal of a leader should always be to “maintain his state” and to “achieve great things,” both of which require power and will increase the power of the ruler. Many have interpreted his arguments as justification for the adage-"the ends justify the means" where upon rulers are allowed to do what they wish in the stated goal of protecting the State. Others believe that Machiavelli was exposing the dangers and threats of single dictatorial rule. What is clear is that many leaders have read and followed his teachings, to both the betterment and sufferings of their peoples and States.
(Other notable works by Machiavelli included Dell’Arte della Guerra [the Art of War], Ritracto delle cose della Magna [Portrait of the affairs of Germany] and Discorsi sopra la prima deca di Tito Livio [Discourses on the First Ten Books of Titus Livy])