This book examines the long history and unrecognized depth of German-Turkish relations, particularly with regard to the mutually formative processes of religious identities and institutions. Opposing the commonly held assumption that Europe is the abode of secularism and enlightenment, while the lands of Islam are the realm of backwardness and fundamentalism, the authors observe that, Germany, as the case in point, both historically and contemporarily has treated religion as a core aspect of communal and civilizational identity and framed its institutions accordingly. Further, there has been, and continues to be, a mutual exchange in this regard between Germany and both the Ottoman Empire and modern Turkey. Definition of identity and regulation of communities have been explicitly based on religion until the early and since the late twentieth century. The period in between, often treated as normative for being identified with secular and national communities, now appears as an exception.