Enlightenment

After asceticism and concentrating on meditation and Anapana-sati (awareness of breathing in and out), Siddhartha is said to have discovered what Buddhists call the Middle Way—a path of moderation away from the extremes of self-indulgence and self-mortification. He accepted a little milk and rice pudding from a village girl named Sujata, who wrongly believed him to be the spirit that had granted her a wish, such was his emaciated appearance. Then, sitting under a pipal tree, now known as the Bodhi tree in Bodh Gaya, India, he vowed never to arise until he had found the Truth. Kaundinya and the other four companions, believing that he had abandoned his search and become undisciplined, left. After 49 days meditating, at the age of 35, he attained Enlightenment; according to some traditions, this occurred approximately in the fifth lunar month, and according to others in the twelfth. Gautama, from then on, was known as the Buddha or "Awakened One." Buddha is also sometimes translated as "The Enlightened One." Often, he is referred to in Buddhism as Shakyamuni Buddha or "The Awakened One of the Shakya Clan."

At this point, he is believed to have realized complete awakening and insight into the nature and cause of human suffering which was ignorance, along with steps necessary to eliminate it. This was then categorized into 'Four Noble Truths'; the state of supreme liberation—possible for any being—was called Nirvana. He then allegedly came to possess the Nine Characteristics, which are said to belong to every Buddha.

According to one of the stories in the Āyācana Sutta (Samyutta Nikaya VI.1), a scripture found in the Pāli and other canons, immediately after his Enlightenment, the Buddha was wondering whether or not he should teach the Dharma to human beings. He was concerned that, as human beings were overpowered by greed, hatred and delusion, they would not be able to see the true dharma, which was subtle, deep and hard to understand. However, Brahmā Sahampati, interceded and asked that he teach the dharma to the world, as "there will be those who will understand the Dharma". With his great compassion to all beings in the universe, the Buddha agreed to become a teacher.

Formation of the sangha
Painting of the first sermon depicted at Wat Chedi Liem in Thailand.

After becoming enlightened, two merchants whom the Buddha met, named Tapussa and Bhallika became the first lay disciples. They are given some hairs from the Buddha's head, which are believed to now be enshrined in the Shwe Dagon Temple in Rangoon, Burma. The Buddha intended to visit Asita, and his former teachers, Alara Kalama and Uddaka Ramaputta to explain his findings, but they had already died.

The Buddha thus journeyed to Deer Park near Vārāṇasī (Benares) in northern India, he set in motion the Wheel of Dharma by delivering his first sermon to the group of five companions with whom he had previously sought enlightenment. They, together with the Buddha, formed the first saṅgha, the company of Buddhist monks, and hence, the first formation of Triple Gem (Buddha, Dharma and Sangha) was completed, with Kaundinya becoming the first stream-enterer. All five soon become arahants, and with the conversion of Yasa and fifty four of his friends, the number of arahants swelled to 60 within the first two months. The conversion of the three Kassapa brothers and their 200, 300 and 500 disciples swelled the sangha over 1000, and they were dispatched to explain the dharma to the populace.

It is unknown what language the Buddha spoke, and no conclusive documentation has been made at this point. However, some modern scholars, primarily philologists, believe it is most likely that the Buddha spoke a vulgate then current in eastern India, Mâgadhî Prakrit.

Travels and teaching
Buddha with his protector Vajrapani, Gandhara, 2nd century CE, Ostasiatische Kunst Museum

For the remaining 45 years of his life, the Buddha is said to have traveled in the Gangetic Plain, in what is now Uttar Pradesh, Bihar and southern Nepal, teaching his doctrine and discipline to an extremely diverse range of people— from nobles to outcaste street sweepers, mass murderers such as Angulimala and cannibals such as Alavaka. This extended to many adherents of rival philosophies and religions. The Buddha founded the community of Buddhist monks and nuns (the Sangha) to continue the dispensation after his Parinirvāna (Pāli: Parinibbāna) or "complete Nirvāna", and made thousands of converts. His religion was open to all races and classes and had no caste structure. He was also subject to attack from opposition religious groups, including attempted murders and framings.
A Tang Dynasty (618–907 AD) Chinese silk landscape painting depicting the young Sakyamuni shaving his head. This is one of the earliest visual presentations of the Gautama Buddha in the history of painting

The sangha travelled from place to place in India, expounding the dharma. This occurred throughout the year, except during the four months of the vassana rainy season. Due to the heavy amount of flooding, travelling was difficult, and ascetics of all religions in that time did not travel, since it was more difficult to do so without stepping on submerged animal life, unwittingly killing them. During this period, the sangha would retreat to a monastery, public park or a forest and people would come to them.

The first vassana was spent at Varanasi when the sangha was first formed. After this, he travelled to Rajagaha, the capital of Magadha to visit King Bimbisara, in accordance with his promise after enlightenment. It was during this visit that Sariputta and Mahamoggallana were converted by Assaji, one of the first five disciples; they were to become the Buddha's two foremost disciples. The Buddha then spent the next three seasons at Veluvana Bamboo Grove monastery in Rajagaha, the capital of Magadha. The monastery, which was of a moderate distance from the city centre was donated by Bimbisara.

Upon hearing of the enlightenment, Suddhodana dispatched royal delegations to ask the Buddha to return to Kapilavastu. Nine delegations were sent in all, but the delegates joined the sangha and became arahants. Neglecting worldly matters, they did not convey their message. The tenth delegation, led by Kaludayi, a childhood friend, resulted in the message being successfully conveyed as well as becoming an arahant. Since it was not the vassana, the Buddha agreed, and two years after his enlightenment, took a two month journey to Kapilavastu by foot, preaching the dharma along the way. Upon his return, the royal palace had prepared the midday meal, but since no specific invitation had come, the sangha went for an alms round in Kapilavastu. Hearing this, Suddhodana hastened to approach the Buddha, stating "Ours is the warrior lineage of Mahamassata, and not a single warrior has gone seeking alms", to which the Buddha replied

That is not the custom of your royal lineage. But it is the custom of my Buddha lineage. Several thousands of Buddhas have gone by seeking alms

Suddhodana invited the sangha back to the royal palace for the meal, followed by a dharma talk, after which he became a sotapanna. During the visit, many members of the royal family joined the sangha. His cousins Ananda and Anuruddha were to become two of his five chief disciples. His son Rahula also joined the sangha at the age of seven, and was one of the ten chief disciples. His half-brother Nanda also joined the sangha and became an arahant. Another cousin Devadatta also became a monk although he later became an enemy and tried to kill the Buddha on multiple occasions.

Of his disciples, Sariputta, Mahamoggallana, Mahakasyapa, Ananda and Anuruddha comprised the five chief disciples. His ten foremost disciples were completed by the quintet of Upali, Subhoti, Rahula, Mahakaccana and Punna.

In the fifth vassana, the Buddha was staying at Mahavana near Vesali. Hearing of the impending death of Suddhodana, the Buddha went to his father and preached the dharma, and Suddhodana became an arahant prior to death. The death and cremation led to the creation of the order of nuns. Buddhist texts record that he was reluctant to ordain women as nuns. His foster mother Maha Pajapati approached him asking to join the sangha, but the Buddha refused, and began the journey from Kapilavastu back to Rajagaha. Maha Pajapati was so intent on renouncing the world that she led a group of royal Sakyan and Koliyan ladies, following the sangha to Rajagaha. The Buddha eventually accepted them five years after the formation of the Sangha on the grounds that their capacity for enlightenment was equal to that of men, but he gave them certain additional rules (Vinaya) to follow. This occurred after Ananda interceded on their behalf. Yasodhara also became a nun, with both becoming arahants.
Devadatta tries to attack the Buddha. Picture of a wallpainting in a Laotian monastery.

During his ministry, Devadatta (who was not an arahant) frequently tried to undermine the Buddha. At one point Devadatta asked the Buddha to stand aside to let him lead the sangha. The Buddha declined, and stated that Devadatta's actions did not reflect on the Triple Gem, but on him alone. Devadatta conspired with Prince Ajatasattu, son of Bimbisara, so that they would kill and usurp the Buddha and Bimbisara respectively. Devadatta attempted three times to kill the Buddha. The first attempt involved the hiring of a group of archers, whom upon meeting the Buddha became disciples. A second attempt followed when Devadatta attempted to roll a large boulder down a hill. It hit another rock and splintered, only grazing the Buddha in the foot. A final attempt by plying an elephant with alcohol and setting it loose again failed. Failing this, Devadatta attempted to cause a schism in the sangha, by proposing extra restrictions on the vinaya. When the Buddha declined, Devadatta started a breakaway order, criticising the Buddha's laxity. At first, he managed to convert some of the bhikkhus, but Sariputta and Mahamoggallana expounded the dharma to them and succeeded in winning them back.

When the Buddha reached the age of 55, he made Ananda his chief attendant.

Death / Mahaparinirvana