The Enlightenment did not end with the French Revolution but extended into the nineteenth century, effecting a transformation to modernity. By 1850, science became increasingly institutionalized and technology hastened transmission of cultural exchange. Restricting Enlightenment to solitary movements, philosophic text, or national contexts ultimately creates insular interpretations. The Enlightenment was instead a transnational phenomenon, of interconnected communities, from diverse geographical and cultural spaces. A revealing example is the Delessert family. Their British-Franco-Swiss network demonstrates the uniqueness, extent, and duration of the Enlightenment. This network’s origins lie in the 1680s. French and British desires for stability resulted in contrasting policies. Toleration, through partial rights, let British Dissenters become leading educators, manufacturers, and natural philosophers by 1760. Conversely, Huguenots were stripped of rights. Thousands fled persecution, and France’s rivals profited by welcoming waves of industrious Huguenots. French refugee communities became vital printing centres, specializing in Enlightenment attacks on the Ancien régime, and facilitated the expansion of the Delessert network. The Delessert banking family made a generational progression from Geneva to Lyon to Paris, linking them to Jean-Jacques Rousseau. His friendship fostered passions for botany and education. The Delesserts parlayed this into participation in Enlightenment science and industry, connecting them to the Lunar Society, Genevan radicals, and British reformers. By 1780, a transition toward modernity began. Grand Tours shifted from places of erudition to practical sites of production. Lunar men sent sons to the Continent for practical education, as Franco-Swiss visited English manufactories and Scottish universities to expand knowledge. Moderates greeted the French Revolution with enthusiasm. In the early 1790s this changed significantly. Royalist mobs threatened Lunar men, destroying property, in Birmingham. In France, moderates tried to defend the monarchy from republican mobs. Even so, the network, fragmented both by revolution and war, continued espousing reform and assisting members who were jailed, endangered, or escaping to America. The Delessert network reconnected in 1801. Franco-Swiss toured Britain as Britons visited Paris, gathering at the hôtel Delessert, a crossroads of the Enlightenment. New societies encouraged science, industry, and philanthropy. Enlightenment exchange continued, despite warfare, into the nineteenth century. Industrial partnerships and scientific collaborations, formed during the peace, circumvented trade barriers. Over three generations (1760-1850) cosmopolitanism helped usher in a transition to modernity. Ultimately, the Delessert network’s endurance challenges traditional interpretations of the Enlightenment, and the Industrial Revolution.