The socio-cultural background of boundary delimitation in medieval Poland with special attention to the consequences of the proliferation of artificial linear boundaries is a subject that has not been the object of much study in history works. Yet it is important to examine this background if we are to understand some of the changes that took place in medieval Poland. The term boundary refers to a material reality whereby space is organised and to a notion used to construct a view of the world. The rise and spread of boundary delineation clearly followed several socioeconomic processes that affected the Polish provinces between the eleventh and the sixteenth centuries: demographic growth, the emergence and development of ecclesiastical and private land property, various settlement movements, deforestation of vast areas, the foundation of numerous villages and towns under German law, and, during the late Middle Ages, an increase in land transactions. These changes began in Silesia, Little Poland, and Great Poland, and reached Pomerania and Masovia later.¹ This chapter looks at the socio-cultural context of these delineations.