Benedict of Nursia

The Rule of St. Benedict is seventy-three short chapters telling a community how to pray, work, eat, sleep, and treat each other. For fifteen hundred years it organised Western monasticism, and through monasticism it organised the preservation of every classical text we still have. Without Benedict's monks copying manuscripts in the dark centuries after Rome fell, we wouldn't have Plato or Aristotle in our libraries. The Rule itself is also still readable — moderate, kind, weirdly modern.