The object of this paper is to establish the meaning and relevance of recovering the contents of pagan religion practiced by ancient Roman Republic, as the basis of the civil lifestyle conceived by Machiavelli in his idea of a mixed republic, through Discourses on Livy, one of his most mature political works. Here we can determine that Machiavelli, while searching to establish a civil religion model, found that not all Roman tradition was equally useful to him. Thus, ruminations on Roman religious tradition by authors such as Cicero or Lucretius, enable him, on the one hand, to sharpen his critical thinking regarding to the role played by religious beliefs and practices as forms of domination achieved through manipulation of fear and superstition. On the other hand, through Roman history and tradition while following Titus Livy, he finds that such critical stances are the expression of the crisis of the Republic, lead towards a dead-end, weaken legitimate authority, cause turmoil, and culminate in tyranny. Consequently, within the narrative of the Paduan historian, Machiavelli finds the model he was seeking for, an instrumentum regni that brings together all levels of society, helps to recognize authority, legitimizes hierarchies, and educates both dominated people and dominators, civitas becoming the beginning and end of all things. By following the search undertaken by Machiavelli it is possible to understand his purpose, that is to say, to refine his criticism of the period's dominant religion: Christianity. Therefore, far from seeking a reestablishment of paganism (something that would have been absurd at the time), his goal was not to destroy or replace Christianity, but to reform and adapt it to the conditions and needs of the new concept of a mixed republic. [ABSTRACT FROM AUTHOR]