From roughly 1500 to 1800, a borderless community of scholars governed itself by reputation alone. Share findings, answer letters, acknowledge sources — and your name traveled the same channels as your ideas; steal or fabricate, and so did your disgrace. This networked correspondence carried the Scientific Revolution and the Enlightenment across hostile national and religious lines. The republic called itself open to anyone of merit; in practice it was almost entirely propertied men, with women mostly confined to the salon. Its durable legacy is the norm it established: expose a claim to a community of competent judges before it counts.
It was a country you could not find on any map. The Republic of Letters had no territory, no government, and no army. Its citizens were scholars scattered across Europe, from Naples to Edinburgh, and they had never all met. What held them together was paper. They wrote one another thousands of letters, sharing discoveries, books, and arguments, and they agreed on one rule above all others: that a good idea should travel freely, no matter the nation or church it came from. For three centuries this imaginary republic was the bloodstream of European thought. Through it moved the new science and the new philosophy that would remake the world. The republic was real in its effects and idealized in its self-portrait at the same time. It called itself open to anyone with merit, and it meant it. But the people who could afford paper, postage, and a classical education were almost all propertied men, and the republic of equals was, in practice, a republic of the few.