This paper, based on original research in French state archives and in the archives of the Maronite Church, examines the political-economic ideas and practices that mediated the relationship between Maronite Christianity and the emerging nationalisms of Bilad al-Sham in the period around the close of World War One. This was a time when, in the wake of the devastation of the wartime period, questions of national economic viability came to prominence in Beirut, Damascus and Paris, and when many anticipated an imminent renewal of hostilities in economic form – an echo of the blocades and starvation that, as Elizabeth Thompson and others have shown, had characterized the war in the Middle East itself. While the connection between the Maronite Church, the French state and the political project of Greater Lebanon and Greater Syria are well known and often studied, especially in the context of the Faisal regime and the Paris Peace Conference, the economic aspects of these projects are much less studied. Through an examination of the Maronite Church’s role as an institutional shareholder in infrastructure and energy companies in Mandate-era Lebanon and Syria, and by examining the rhetorical presentation of this role by the Maronite Church, the paper analyzes the way in which this religious institution contributed to the articulation of a newly national Lebanese economy. Through a case study of the Kadisha hydroelectric company in Lebanon, I follow Priya Satia’s work on Iraq during World War One, and argue that modern developmentalism, so often associated with the post-1945 era, in fact has its roots in the inter-war ‘Mandatory’ Middle East. Deploying trans-national and global history methodologies, I also show how Maronite and French actors drew on wider vocabularies of distinctively national economic modernization, such as those generated by the League of Nations, to prophesy a new national prosperity in the 1920s.