The Republic of Letters and the Rise of the West

What role did the Republic of Letters play in Europe's transition to sustained innovation? We combine a corpus of digitized correspondence within the Republic of Letters with European aristocratic genealogies, historical postal routes, and a database of notable individuals to trace the diffusion and consequences of Enlightenment correspondence between 1600 and 1850. We first show that the Republic spread, in part, through aristocratic kinship networks: aristocrats connected to already participating peers entered earlier, and their probability of entry declined sharply with network distance. To isolate a causal channel, we exploit changes in postal distances along pre-existing kinship paths to already-inoculated aristocrats, while controlling directly for local postal access. We then aggregate this variation to European grid cells and estimate the effect of exposure to the Republic on the rise of applied science, innovation, and economic activity. Cells instrumented into the Republic experienced a near- doubling in applied scientists and inventors roughly three decades after first contact, with no pretrends and effects concentrated in scientific and technical correspondence rather than religion or philosophy. These findings suggest that the Republic of Letters helped reshape the geography of innovation before industrialization.