Chronicles the emergence of modern sainthood, analyzing how the Catholic Church legitimized miracles during the Counter-Reformation in southern Europe.During the Counter-Reformation in southern Europe, Catholic Church officials legitimized miracles performed by candidates to sainthood. The Rationalization of Miracles uncovers a tacit understanding between two groups with vested interests in declaring miracles: Catholic Church leaders who sought legitimacy in the wake of the Protestant Schism and religious acolytes who needed Church approval to secure resources for their movements. From this cooperation the institutional field of modern sainthood emerged.During the Counter-Reformation in southern Europe, Catholic Church officials legitimized miracles performed by candidates to sainthood. The Rationalization of Miracles uncovers a tacit understanding between two groups with vested interests in declaring miracles: Catholic Church leaders who sought legitimacy in the wake of the Protestant Schism and religious acolytes who needed Church approval to secure resources for their movements. From this cooperation the institutional field of modern sainthood emerged.During the Counter-Reformation in southern Europe, Catholic Church officials developed rules to legitimize miracles performed by candidates to sainthood. The Rationalization of Miracles uncovers a tacit understanding between central religious officials and local religious activists. Each group had a vested interest in declaring miracles: Catholic Church leaders sought legitimacy in the wake of the crisis of faith created by the Protestant Schism and religious acolytes needed Church approval to secure a flow of resources to their movements. The Church's new procedure of deeming miracles true when there were witnesses of different statuses and the acts occurred in the presence of a candidate's acolyte served the needs of both parties. And by developing rules and procedures for evaluating miracles, the Church rationalƒ°