From the vast yet tension-ridden relationship between Enlightenment and religion, the Center of Excellence places the transformations of the religious and the rational in the center of interest. In the historiography of the humanities – especially that of philosophy – the eighteenth century is conventionally apostrophized as the century of rationalism. Yet this is merely a convention of provisional character since the entire modern age is marked by a continual critical examination of the standards of rationality in all dimensions of human life. More than anything, the flourishing and fertility of scientific research increasingly raises new questions about the standards of rationality in the acquisition and assessment of knowledge gained through scientific means, but also about the standards of rationality for the communication of such knowledge to the still considerable proportion of people without a scientific education. Last but not least, the dimension of the religious itself is also included in discussions on new standards of rationality. The eighteenth century as modern genesis of these discussions provides paradigmatic material for the Center of Excellence's examinations of the transformations of religion and rationality. While following recent research tendencies in the cultural sciences, the Center of Excellence "Enlightenment – Religion – Knowledge" sets new emphasis with the field of "Enlightenment and Religion" through particularly illuminating approaches. The core of the research focuses on the processes of contact, transference, influence, interaction, interconnection and transformation of discourses on rationality and religion which go beyond questioning the dialectics of the rational or the otherness of reason. The Center of Excellence understands the legacy of Enlightenment rationality not as a linear process but as the self-reflexivity formed through the transformations of ratio and religion.