This dissertation examines the case of 250-300,000 largely Orthodox Christian refugees who fled Ottoman Bosnia and Hercegovina for the Habsburg Empire during the uprisings of 1875-1878. The violence during this period started out as a peasant uprising, but over the course of three years cascaded into revolts and violence across the Ottoman Balkans and led to a major European diplomatic crisis. The Treaty of Berlin of 1878, which ended the violence, reconfigured the political geography of the Balkans, making the former Ottoman provinces of Montenegro, Romania, and Serbia independent; giving a sweeping autonomy to Bulgaria, and handing over to Austria-Hungary the administration of a nominally Ottoman Bosnia and Hercegovina. Refugees played an under-appreciated role in the international and domestic politics of the period, and this dissertation argues that forced migration was in fact one of the key considerations of Great Power diplomacy. Forced migration offered a means to measure degree of violence, and control over population movement offered a way for empires to lay claims to legitimacy. In a similar manner, philanthropists and international humanitarians used forced migration to build and advocate for their own civic spheres. The dissertation argues that during this period, the modern category of "refugee" was defined as states developed processes to manage refugees domestically and to create international policies for refugee aid and return.