This article examines the life and deeds of Devadatta, the man who opposed the Buddha and attempted to take over control of the Saṃgha from him, and studies too the circumstances of his schism, using early Pali and Chinese sources, both sutras and commentaries. Devadatta has been reviled throughout Buddhist history as the exemplification of an evil man. Our conclusions are as follows.

The Northern and Southern Transmissions differ regarding Devadatta's background. According to the former, Devadatta was the brother of Ānanda, and, since his father was a brother of King Suddhodana, he was a cousin of Sakyamuni on his father's side. However the traditions associated with the Southern Transmission says that he was the younger brother of Sakyamuni's wife, and came from Devadaha. And since his mother was Suddhodana's younger sister, he was both Sakyamuni's brother-in-law and his cousin on his mother's side. There is no way of knowing if either tradition is close to historical fact. Over and above that, it is hard to imagine that Devadatta became ordained at the same time as his "brother" Ānanda, and, considering that Devadatta wanted to transfer the leadership of Sakyamuni's Saṃgha to himself, we assume in this article that the Southern Transmission is perhaps closer to historical fact, since his actions are easier to understand logically if Devadatta was not Ānanda's brother but rather Sakyamuni's brother in law.

As is mentioned in Source Material 3, "Sources by Topic in the Buddha Biographies and Related Documents", only narrative accounts remain of episodes related to Devadatta's early years, before his renunciation. These concern incidents that demonstrated his rivalry with Sakyamuni, such as winning a bride. Since though there was a twenty-five year age difference between the two men, there is probably little substance in such stories. When he was around twenty, Devadatta became ordained, together with his friends Anuruddha, Bhaddiya, Ānanda, Kimbila, Bhagu, and their barber Upāli. This was some ten years after the Buddha's enlightenment, when he was around 45. It was about that time that Sakyamuni's disciples were permitted to ordain followers by means of the Triple Refuge. Neither Devadatta nor Ānanda became bhikkhus by the direct invitation of Sakyamuni; who ordained them is not certain, but it is possible they became ordained with a bhikkhu, who was perhaps an associate of the Kassapa brothers, acting as sponsor (upajjhāya).

Based on the regulation that a bhikkhu had to spend the first ten years after his ordination as a "live-in pupil" (saddhivihārika) under the tutelage of the senior bhikkhu who was his preceptor (upajjhāya), Devadatta must have spent at least twelve years undergoing training. Since the upajjhāya was a practitioner in the ascetic tradition, Devadatta too would have followed this type of training. As his efforts bore fruit, his name increasingly became known within the society of his time. This occurred some nine years after he left his master.

He went to Rajagāha, where his powers brought him the patronage of Prince Ajātasattu, the son of King Bimbisara of the new kingdom of Magadha. Ajātasattu wanted to usurp his father's throne. The early Buddhist sources, which wanted to paint Devadatta as an evil man, created the legend that Devadatta had even swallowed Ajātasattu's spittle. Ajātasattu was around twenty at that time, and Devadara was 41.

The political and religious situation in Rajagāha at that time can be seen as a rivalry between Bimbisara and the Buddha on one side, and Ajātasattu and Devadatta on the other. Also, Ajātasattu and Devadatta may have been supported by the influence of Jainism.

Devadatta's power gradually increased, and six years later, when he was 47 and the Buddha 72, he finally made his move. Using the Buddha's old age as a pretext, he suggested that he assume leadership of the Saṃgha by taking over the Bhikkhu Saṃgha of Magadha, which was under the guidance of Sakyamuni and no doubt of Sariputta and Moggalana, from his own base in Gaya. Sakyamuni emphatically repudiated his claim. Because he also made what was virtually a public announcement that he did not recognize Devadatta's authority, any possibility of reconciliation on Devadatta's part was destroyed, and so he felt compelled to destroy the harmony of the Saṃgha.

He intended to cause a schism in the Saṃgha, by demanding that the five severe rules he proposed be made compulsory by the Buddha. These were rules of conduct associated with the ascetic life prized by the older stratum of Buddhist practitioners. For Devadatta, they represented ammunition to draw popular sentiment towards himself. Though Devadatta probably did not make the proposition seriously, for form's sake he himself had to be pursuing such a life-style. The group under Sakyamuni's guidance, on the other hand, continued to follow a more relaxed method of religious training, based on the Buddha's more moderate and rational leadership. In a contest over royal authority, Ajātasattu took control of Rajagāha. In the meantime, the Buddha's group grew in strength, both because of Sakyamuni's own prestige as founder and because an increasing number of bhikkhus could be ordained by means of the Triple Refuge or through a preceptor. Such bhikkhus tended to be critical of old-fashioned extreme ascetic practices. As a result, Devadatta's attempts to bring about schism ended in failure. Since the early Buddhist sources we possess today were edited by those associated with Sakyamuni's group, they branded Devadatta as the most evil of men, and his lineage was expunged from the history of the Saṃgha. In fact, the records of the Chinese traveller-monks Faxian, Yi Jing and Xuanzang tell us that as late as the seventh century there were still groups of ascetics in India who looked to Devadatta as their founder, not Sakyamuni.