This project explores modern adaptations of medieval mysticism, societal forms, and gothic architecture, which create a foundation for modernist aesthetics in the first three decades of the twentieth century. I approach the medieval period as it is both adapted by modernists to enrich the poetic and artistic media of their own time, and, as expressionist theorists like Wassily Kandinsky, Ernst Bloch, and Wilhelm Worringer conclude, as an adaptable or adapting force that emerges at various historical intervals according to a principle of necessity. In doing so, I hope to unmask the difficult interdependency between medieval inheritances and modernist concepts of union, communion, and community, especially as they permeate German expressionist poetry, art, and architecture. In three parts, I will explore the specific dimensions of modernist artistic production, culminating in an argument for a theory of modernism as the embodiment of tensions between secular and sectarian, spiritual and materialist, progressive and regressive historical forces.