India during the lifetime of the Buddha was in a state of religious and cultural ferment. Sects, teachers, and wandering ascetics abounded, espousing widely varying philosophical views and religious practices. Some of these sects derived from the Brahmanical tradition (see Hinduism), while others opposed the Vedic and Upanishadic ideas of that tradition. Buddhism, which denied both the efficacy of Vedic ritual and the validity of the caste system, and which spread its teachings using vernacular languages rather than Brahmanical Sanskrit, was by far the most successful of the heterodox or non-Vedic systems. Buddhist tradition tells how Siddhartha Gautama, born a prince and raised in luxury, renounced the world at the age of 29 to search for an ultimate solution to the problem of the suffering innate in the human condition. After six years of spiritual discipline he achieved the supreme enlightment and spent the remaining 45 years of his life teaching and establishing a community of monks and nuns, the sangha, to continue his work.
After the Buddha's death his teachings were orally transmitted until the 1st cent. B.C., when they were first committed to writing (see Buddhist literature; Pali). Conflicting opinions about monastic practice as well as religious and philosophical issues, especially concerning the analyses of experience elaborated as the systems of Abhidharma, probably caused differing sects to flourish rapidly. Knowledge of early differences is limited, however, because the earliest extant written version of the scriptures (1st cent. A.D.) is the Pali canon of the Theravada school of Sri Lanka. Although the Theravada [doctrine of the elders] is known to be only one of many early Buddhist schools (traditionally numbered at 18), its beliefs as described above are generally accepted as representative of the early Buddhist doctrine. The ideal of early Buddhism was the perfected saintly sage, arahant or arhat, who attained liberation by purifying self of all defilements and desires.