One of more poorly understood aspects of the Ottoman Empire has been the flourishing of Sufi mysticism under its auspices. This study tracks the evolution of the Halveti order from its modest origins in medieval Azerbaijan to the emergence of the influential Sa'baniyye, whose range once extended throughout the Empire. By carefully reconstructing the lives of formerly obscure figures in the history of the order, a complex picture emerges of the connections among Halveti groups, the state, and society.