Buddhism arose more than 2500 years ago in India in an atmosphere of great philosophical ferment. It was the atmosphere in which the sacrificial religion was systematized in the Mimamsa, the philosophical ideas of the Upanisads were crystallized, and the ideas of independent thinkers, not owing allegiance to either, were trying to gain their foothold in the Indian thought. All these philosophies were philosophies of life according to the reality as understood by their profounder. All the philosophical sects at that time, except the Chaarvaakas, were indeed ascetic.
Buddhism arose out of the sects independent of the Mimamsa and the Vedanta. It incorporated what it considered to be the best from all, both the orthodox and the heterodox. It became one of the world's greatest religions, and contributed one of the highest of philosophies.
The founder of Buddhism, Gautama, known to the world as the Buddha, the Enlightened, participated in a critical and creative movement to synthesize ancient, traditional worldviews, which vied for the collective heart of India in his time. Interestingly, some of the most influential thinkers the world has ever known such as Confucius and Lao-tzu in China, Zoroaster and Socrates in Persia and in Greece, Jeremiah and Deutero Isaiah in Israel also belonged to the same period with a variation of a few decades on either side. The Buddha was the most influential individual to emerge from the then intellectually and religiously stimulating period in India.
The Buddha evoked the admiration of even the orthodox Mimamsakas and Vedantins by the gentleness and nobility of his character, and also by the clarity and simplicity of his teachings. He was accordingly absorbed into the Hindu pantheon. His philosophy, in its latest stages, looked so similar to the Vedanta that it was eventually assimilated to it. As such, Buddhism gradually lost justification for separate existence and disappeared from India, except for a few border areas.