Twentieth-century European history was marked by changing borders and the flight and forced relocation of a staggering number of people from many ethnic groups. An estimated 60–80 million people (approximately 10 percent of all Europeans) were affected by involuntary population movements over the course of the twentieth century. These massive movements of people—and the human, social, and political ramifications—are intertwined not only with the ideology and politics of National Socialism but also, more broadly, with the history of European nationalism since the nineteenth century. The legacy of the forced relocation of more than twelve million Germans from previously German Eastern territories at the end of the Second World War has to be considered in the context of these larger ethno-national phenomena.

Since the end of the Cold War, the opening of material and immaterial borders facilitated new opportunities for communication and travel, as well as increased accessibility to archives—all of which contributed to new research opportunities on Central and Eastern European history and the above-mentioned legacies of nationalism. Over the past decades the history of border regions, especially in Central and Eastern Europe, has thus garnered renewed attention in the academic realm. This chapter focuses on the German-Polish border region. From the perspective of Germany, the politically most sensitive issues related to the changing German-Polish border are flight, expulsion, and the forced relocation of ethnic Germans.