This dissertation analyzes state-formation, the development of historical consciousness, and the construction of identities in medieval Europe. The source materials used to examine these topics are the records from a series of disputes between the Teutonic Knights and Polish and Pomeranian rulers during the thirteenth and fourteenth centuries. The first part situates these conflicts between the Teutonic Knights and their neighbors and benefactors in the context of the ethnic, religious, cultural, and political borderland society of the thirteenth-century south Baltic littoral. The second part examines how in the early fourteenth century these borderlands were transformed through a complex process of remembering and forgetting into ?bordered lands? of strictly demarcated political boundaries. The nature of the documentary evidence provides a unique opportunity to analyze how communities within Poland and the Teutonic Ordensstaat constructed their own views of their collective identity and history as well as how the views of these communities helped to inform and transform the views of the elites, who traditionally appropriated the role of preserving memories and propagating identities. In 1320 and 1339, in the aftermath of two periods of conflict between Poland and the Ordensstaat, the Papacy ordered legates to conduct inquires into the Polish kings? claims that the Teutonic Knights had illegally seized lands belonging to Poland. The lengthy testimonies of over 150 witnesses provide evidence about how representatives of different social and cultural groups in Poland thought about their role within the nascent Polish kingdom. Although the witnesses were asked by judges to respond to articles proposed by royal lawyers, the witnesses often took this opportunity to talk about whatever they felt relevant, sharing their personal memories of events, or memories which had been passed on to them by members of the various secular and ecclesiastical communities to which they belonged. They also presented reasons that went well beyond the scope of what they were asked ? their own views on ethnicity, history, law, and customs, and what role these played in defining where and what the Kingdom of Poland was, as well as who should be included within its boundaries.