This article summarizes the history of the relics of St Barbara in Althaus Kulm (Starogród Chełmiński), a topic with extensive research in Polish and German circles, but only recently addressed by scholarship in English. It begins with an overview of the relics’ history and a summary of St Barbara’s vita, pointing out the quick rise in her cult in the Teutonic Order’s Prussian territory (Ordensland). Following this, it assesses the function of the relics through three lenses: warfare, daily life, and as a symbol of the Order’s power using three methodological frameworks. These are hierophany (manifestations of the sacred) for warfare, naming practices for studying the impact of St Barbara on the local population, and as a reflection of the Order’s territorial power (Landesherrschaft). The article ultimately demonstrates that the relics were a significant element of the multifaceted structure of religious life in medieval Prussia, both within and outside of the Teutonic Order. Appended to the text are two previously unpublished accounts of the relics of St Barbara and their arrival in Althaus, demonstrating the reputation of the shrine not just in the Ordensland, but within Christendom. It concludes with a summary of the research findings, and a consideration of these findings in light of more ‘recent’ interpretations of the Teutonic Order and the Prussian Crusades.