Around 500 BCE, an Indian prince named Siddhartha Gautama — having concluded that desire was the root of suffering and that suffering was the root of life — left his palace and started preaching what would become Buddhism. Within his lifetime he had a few thousand followers in the Gangetic plain. The faith's first great patron came two centuries later: the emperor Ashoka, who after the bloodbath of his Kalinga campaign converted, and dispatched missionaries as far as Sri Lanka and the Hellenistic kingdoms to the west. Within five centuries, the teachings had spread along the Silk Road into central Asia. By the seventh century CE, Buddhism had become dominant or ascendant across China, Korea, Japan, Vietnam, and most of Southeast Asia, with Tibet's conversion just beginning and Mongolia's still nine centuries away. It accomplished this without a centralizing authority, without a state imposing it by the sword, and largely without violence — by the footwork of monks.
Buddhism's portability is one of the more interesting stories in religious history. It travelled because it was easy to translate — its core claims are propositional rather than tied to a particular sacred geography, so a sutra lost none of its truth in Chinese or Sogdian. It travelled the trade routes themselves: merchants funded the cave-monasteries at Dunhuang and Bamiyan as way-stations, and pilgrims like the Chinese monk Xuanzang, who walked to India and back in the 630s, returned with cartloads of texts to translate. It travelled because it offered something the existing local religions did not: a psychological technology — meditation, mindfulness, the systematic analysis of mind — that could be adopted alongside ancestor worship or Daoism rather than demanding their abolition. And it travelled because monastic communities are excellent at long-distance institution-building: copying texts, training disciples, founding new monasteries that founded others in turn. By the time Buddhism reached Japan in the sixth century, it had picked up Greco-Bactrian artistic conventions in Gandhara — which is why early Buddhas look faintly Apollonian — Confucian moral concerns in China, and tantric practices on the way through the Himalayas. Each transmission adapted the religion to local conditions while preserving the core, splitting into the Theravada of the south and the Mahayana of the north.
Buddhism's renewed influence in the West — through secular mindfulness programs in hospitals and schools, through the cognitive-behavioural and acceptance therapies that borrow its techniques, through Silicon Valley's repackaging of meditation as a productivity and resilience tool — is the latest run of an ancient pattern. Apps like Headspace and Calm strip the metaphysics and keep the method, exactly as Chinese literati once kept the meditation and folded it into their own world. The religion has never stopped exporting itself by making its core practices teachable in any cultural language — even the language of neuroscience and the quarterly review.