The title says it all: What would be the world look like if the Persians under Darius I had successfully conquered the Greek city-states and made Greece into a satrapy? Could this mean that the West (or what arises in Europe in its place) become overall and customarily more open to new ideas and more tolerant than in OTL? Maybe, much later, no Transatlantic Slave Genocide, as the Persians famously banned slavery?
Discuss.