In this article, Maurizio Viroli introduces the various ways in which political theorists of the Italian Renaissance began to move away from traditional thinking about natural law. Machiavelli maintains a suggestive silence with respect to natural law, and considers instead the positive or written law of states, without reference to the philosophical and theological sources of its authority. Although Machiavelli dispenses with the language of natural law, he continues to place tremendous importance on laws, and argues that it is good laws that make a government legitimate. Another important thinker of the time, Francesco Guicciardini, was far more explicit in his rejection of natural law. Espousing a kind of radical realism, Guicciardini challenges the idea that there could be any principles of human action that transcend individual historical cases. For Guicciardini, government is established, not on any ideal, but upon sheer force thinly veiled by pretensions of honesty and justice. Giovanni Botero shares Guicciardini’s view of the harsh reality of politics, and develops the idea of “reason of state” to explain why, in his view, a state must often use immoral actions to preserve its existence and further its interests. Language about reason of state ultimately sidesteps engagement with natural law, not so much by refuting it, but by arguing that it is irrelevant to political concerns.