His given name was Siddhartha and his family name Gautama (or Gotama). He was born the son of a king of the Sakya clan of the Kshatriya, or warrior, caste (hence his later epithet Sakyamuni, the sage of the Sakyas) in the Himalayan foothills in what is now S Nepal. It was predicted at his birth that he would become either a world ruler or a world teacher; therefore his father, King Suddhodana, who wished Siddhartha to succeed him as ruler, took great pains to shelter him from all misery and anything that might influence him toward the religious life.

Siddhartha spent his youth in great luxury, married, and fathered a son. The scriptures relate that at the age of 29, wishing to see more of the world, he left the palace grounds in his chariot. He saw on successive excursions an old man, a sick man, a corpse, and a mendicant monk. From the first three of these sights he learned the inescapability of suffering and death, and in the serenity of the monk he saw his destiny. Forsaking his wife, Yashodhara, and his son, Rahula, he secretly left the palace and became a wandering ascetic.

Siddhartha first studied yogic meditation under the teachers Alara Kalama and Udraka Ramaputra, and after mastering their techniques, decided that these did not lead to the highest realization. He then undertook fasting and extreme austerities, but after six years gave these up fearing that they might cause his death before he attained illumination. Taking moderate food, he seated himself under a pipal tree at Bodh Gaya and swore not to stir until he had attained the supreme enlightenment. On the night of the full moon, after overcoming the attacks and temptations of Mara, the evil one, he reached enlightenment, becoming a Buddha at the age of 35.

Leaving what was now the Bodhi Tree, or Tree of Enlightenment, he proceeded to the Deer Park at Sarnath, N of Benares (Varanasi), where he preached his first sermon to five ascetics who had been with him when he practiced austerities. They became his first disciples. The first sermon, known as the setting into motion of the wheel of the dharma, contained the basic doctrines of the four noble truths and the eightfold path.

For the remainder of his life he traveled and taught in the Gangetic plain, instructing disciples and giving his teaching to all who came to him, regardless of caste or religion. He spent much of his time in monasteries donated to the sangha, or community of monks, by wealthy lay devotees. Tradition says that he died at the age of 80. He appointed no successor but on his deathbed told his disciples to maintain the sangha and achieve their own liberation by relying on his teaching. He was cremated and his relics divided among eight groups, who deposited them in shrines called stupas.