Religion in the Ottoman world did not follow a consistent trajectory towards national consciousness. This path was full of twists and turns, and if the nation-state was eventually an all-mighty political entity firmly established in the post-Ottoman world by the twentieth century, it became so by building on the legacy of notions, practices, institutions, and mentalities rooted in the Ottoman past, causing many inconsistencies and contradictions within a seemingly impermeable narrative. Comparing the Muslim and non-Muslim transition to the nation-state, this chapter posits that (1) orthodoxy was always a contested issue, reflecting social tensions that undermined cohesion; (2) religion is not an issue solely understandable by theological treatises: it is closely connected to social and economic factors; and (3) the millet system, far from a centuries-long Ottoman institution, was rather short-lived and much more modern than post-Ottoman national historiographies would have it.