The stereotype of the ‘terrible Turk’ has long existed alongside the romantic view of a multicultural, cosmopolitan Ottoman Empire. Assertions of Ottoman ‘tolerance’ have been very enduring even in the academic literature. In recent decades Ottoman historians have worked hard to historicise both violence and more peaceful relations, between both state and society and within society itself. Tolerance is now better understood as a strategy of rule rather than a value in and of itself. In addition, this was a far-flung empire that lasted for over 600 years, and no one model can hold for all places and all times within the sultan’s domains. Beginning with the Ottoman conquest of the Balkans in the fourteenth century, this chapter considers not only more familiar topics, such as non-Muslim conversion to Islam, but also highlights the fact that most religious persecution in the empire, when it occurred, was directed at non-conforming Muslims, however defined. The rise of the Shi’a Safavid Empire in the east and the ruling elite’s close relationship to Sufi Islam were both major sources of tension and, at times, outright violence. At the same time, communal elites usually shared a strong interest in the maintenance of religious boundaries; this attitude contributed to social peace.