In the present essay, Anton Baumstark surveys the key developments in the origin and evolution of the Byzantine liturgical rite. Baumstark begins with the assumption that, in their earliest forms, the “western” (Roman) and “eastern” (Byzantine) liturgies were quite similar. However, for various reasons based on historical circumstances, the two traditions developed distinct liturgical traditions that increasingly diverged from one another over time. Baumstark notes that previous works have focused on the development of the unique features of the Roman liturgical rite, so he focuses the present study on the Byzantine rite. Baumstark conducts this survey by comparing various liturgical materials from the Byzantine tradition from various historical periods. In doing so, Baumstark attempts to locate the historical circumstances that precipitated the unique developments of the Byzantine liturgy.