The founder of Buddhism was Gautama Buddha.
He was born in 566 BC at Lumbini, Nepal.
One night he left his palace in search of truth and ultimately attained the true knowledge at Bodhgaya. He then began to be called Buddha or the enlightened one.
He delivered his first sermon at Sarnath near Varanasi. This event is known as dhamma-chakra-pravartana (turning of the wheel of law).
He also established his sangha here.
He died at the age of 80 in 486 B.C. at Kusinara or Kushinagar near Gorakhpur in eastern UP.
According to Gautama Buddha, the world is full of sorrow and people suffer on account of desires.
If desires are conquered nirvana will be attained, that is, man will be free from the cycle of birth and death.
He taught that a person should avoid the excess of both luxury and austerity. He prescribed middle path.
The main teachings of Buddhism are encapsulated in the basic concept of four noble truths or Arya Satya and eightfold path or ashtanga marga.
The first noble truth, Buddha said that suffering (dukkha) is the essence of the world and is like an ocean of miseries.
Second noble truth is dukkha samudya i.e. every suffering has a cause.
Third noble truth is dukkha nirodha i.e. suffering could be extinguished.
Fourth noble truth is dukkha nirodha gamini pratipada i.e. there is a path leading to the extinction of dukkha.
He said that everything in this world like birth, old age and death leads to suffering. If one wants to get rid of suffering one has to conquer the desire. This removal of desire can be achieved through eightfold path, these are:
 right faith
 right resolve
 right speech
 right action
 right living
 right effort
 right thought
 right self-concentration
Cause of its spread
Buddhism does not recognize the existence of God and the soul.
It particularly won the support of the lower orders as it attacked the varna system.
People were admitted into Buddhist order without any consideration of caste.
Women also were admitted to the Sangha and thus brought on a par with men.
In comparison with Brahminism, Buddhism was liberal and democratic.
Buddha tried to fight evil by goodness and hatred by love.
The use of Pali, the language of common people, also contributed to the spread of Buddhism. It facilitated the spread of Buddhist doctrines among the common people.
Gautam Buddha also organized the sangha or religious order, whose doors were open to everybody, irrespective of caste and sex.
There are three elements in Buddhism, Buddha, Dhamma, and Sangha.
The monarchies of Magadha, Kosala and Kausambi and several Republican states and their people adopted this religion.
Two hundred years after the death of the Buddha the famous Maurya King Ashoka embraced Buddhism.
Ashoka spread Buddhism into Central Asia, West Asia, and Sri Lanka and thus transformed it into a world religion.
Buddhist scholars created many literary texts like Tripitaka, Milindapanho, Buddhacharita, etc.
Buddhism became an inspiration for the promotion of art and architecture, in the form of stupas, rock-cut caves, and paintings. These can be noticed at Sanchi, Bharhut, Amravati, Ajanta etc.
Buddhism inspired Gandhara and Mathura schools of art.
Buddhism by opening its door to all the classes challenged the superiority of Brahmanism and gave a better social position to lower castes.
Influence of Buddhism:
Buddhism asked people not to accumulate wealth.
It imposes a restriction on the food, dress and sexual behavior of the monks.
They cannot accept gold and silver and they cannot take to sale and purchase.
These rules were relaxed after the death of the Buddha.
Debtors were not permitted to be members of the sangha.
The rule that slaves could not join the sangha helped the slave owners.
Buddhism made an important impact on society by keeping its doors open to women and Shudras.
With its emphasis on non-violence and the sanctity of animal life, Buddhism boosted the cattle wealth of the country.
The earliest Buddhist text Suttanipata declares the cattle to be food givers, beauty and happiness, and thus pleads for their protection.
Buddhism taught the people not to take things for granted but to argue and judge them on merits.
To a certain extent, the place of superstition was taken by logic. This promoted rationalism among people.
Buddhist enormously enriched Pali by their writings. The early Pali literature can be divided into three categories.
 Sayings and teachings of the Buddha
 Rules to be observed by members of the sangha.
 Philosophical exposition of the dhamma.
The Buddhist monasteries developed as great learning centers and can be called residential universities. Nalanda and Vikramshila in Bihar and Valabhi in Gujarat.
The first human statues worshipped in India were probably those of the Buddha.
Various events in the life of the Buddha portrayed in stones. These found at Gaya in Bihar and at Sanchi and Barbhut in Madhya Pradesh.
From the 1st century A.D the panel images of Gautam Buddha began to be made.
The Greek and the Indian sculptors worked together to create a new kind of art on the north-west frontier of India, which is known as the Gandhara art.
For the residence of the monks, rooms were hewn out of the rocks and thus began the cave architecture in Barbara hills in Gaya and in western India around Nasik.
Under the impetus of Roman trade Buddhist art flourished in the Krishna delta.
The decline of Buddhism:
In the fourth council during the reign of Kanishka, Buddhism split into two major sects called Hinayana and Mahayana.
Mahayana adopted Sanskrit as its language and started worshipping Buddha in the form of an idol, while Hinayana continued to follow Pali and treated Buddha as a guide.
Buddhism became weak by seventh century AD but the impact of Buddhism can be seen in all spheres of life in Indian history.
By the twelfth century A.D, Buddhism became practically extinct in India.
Gradually the Buddhist monks were cut off from the mainstream of people’s life; they gave up Pali, the language of people, and took Sanskrit, the language of intellectuals.
From the First Century A.D, they practiced idol worship on a large scale and received numerous offerings from devotees.
The rich offerings supplemented by generous royal grants to the Buddhist monasteries made the life of monk easy.
By the Seventh Century A.D, the Buddhist monasteries had come to be dominated by ease-loving people and became center of corrupt practices which Gautam Buddha had strictly prohibited.
The enormous wealth of the monasteries with women living in them led to further degeneration.
For their riches, the monasteries came to be coveted by the Turkish invaders. The Turks killed a large number of Buddhist monks in Nalanda, although some of the monks managed to escape to Nepal and Tibet.