The social contract was introduced by early modern thinkers—Hugo Grotius, Thomas Hobbes, Samuel Pufendorf, and John Locke the most well-known among them—as an account of two things: the historical origins of sovereign power and the moral origins of the principles that make sovereign power just and/or legitimate. It is often associated with the liberal tradition in political theory, because it presupposes the fundamental freedom and equality of all those entering into a political arrangement and the associated rights that follow from the principles of basic freedom and equality. From that starting point, often conceptualized via the metaphor of a “state of nature”, social contract theory develops an account of political legitimacy, grounded in the idea that naturally free and equal human beings have no right to exercise power over one another, except in accordance with the principle of mutual consent.