While good ideas can emerge anywhere, it takes a community to develop and disseminate them. In premodern Europe (1084-1793), there were approximately 200 universities and 150 academies of sciences, which were home to thousands of scholars and created an extensive network of intellectual exchange. By reconstructing interpersonal connections that were made via institutional affiliations, we demonstrate how the European academic landscape facilitated the diffusion of ideas and led cities to develop: examples include botanic gardens, astronomical observatories, and Protestantism. Counterfactual simulations reveal that both universities and academies played crucial roles, with academies being particularly effective at connecting distant parts of the network. Moreover, we show that the diffusion of ideas through the network is remarkably resilient, even if we remove key regions such as France or the British Isles. In Europe, ideas gain prominence when they are channeled effectively by powerful institutions.