This chapter provides the historical context of “early Buddhism”, the roughly four centuries of oral transmission from the death of the Buddha until his teachings were written down for the first time. It recounts how Buddhist doctrine was memorised by chanting aloud, using such mnemonic devices as repetition and ordered lists; it also shows how errors in transmission could have been introduced. Such errors became more likely as Buddhism spread throughout the Indian sub-continent and beyond into Central Asia, the number of monasteries increased, and sectarian differences arose, with each school preserving its own canon. The importance of comparative textual analysis is demonstrated by reference to accounts in Pali, Sanskrit, and Chinese of the Buddha’s first sermon, the founding of the Buddhist Saṅgha (order of monks), and of the First Buddhist Council.