The history of the medieval Baltic is dominated by the crusading movement of the 13th to 15th centuries. The crusades resulted in significant changes to the organisation, ownership and administration of the landscape, with a significant shift in patterns of land use. However, our understanding of the environmental impact of the crusades has been almost exclusively informed by written sources. This paper synthesises existing palynological evidence for medieval landscape transformation in the southeast and eastern Baltic, focusing on the ecological impact of the crusading movement, and considers some key questions, challenges and priorities for future research.