This study describes the origin, development and crisis of the German nineteenth-century project of theology as science. Its narrative is focused on the two predominant theological schools during this period, the Tübingen School and the Ritschl School. Their work emerges as a grand attempt to synthesize historical and systematic theology within the twin paradigms of historicism and German Idealism. Engaging in detail with the theological, historical and philosophical scholarship of the story's protagonists, Johannes Zachhuber reconstructs the basis of this scholarship as a deep belief in the eventual unity of human knowledge. This idealism clashed with the historicist principles underlying much of the scholars' actual research. The tension between these paradigms ran through the entire period and ultimately led to the disintegration of the project at the end of the century. Drawing on a wealth of primary sources, many of which have never been used in English speaking scholarship before, Zachhuber embeds the essentially theological story he presents within broader intellectual developments in nineteenth century Germany. In spite of its eventual failure, the project of theology as science in nineteenth century Germany is here described as a paradigmatic intellectual endeavour of European modernity with far-reaching significance beyond the confines of a single academic discipline.