Second Buddhist council
The Second Buddhist council took place at Vaishali approximately in 383 BCE, seventy years after the Buddha's parinirvāṇa. The Second Council resulted in the first schism in the Sangha, probably caused by a group of rigorist reformists called Sthaviras who split from the majority Mahāsāṃghikas. After unsuccessfully trying to modify the Vinaya, a small group of "elderly members", i.e. sthaviras, broke away from the majority Mahāsāṃghika during the Second Buddhist council, giving rise to the Sthavira sect.
Addition of Vinaya rulesEdit
The Second Council is commonly said to have resulted in the first schism in the Sangha, probably caused by a group of rigorist reformists called Sthaviras who split from the more liberal, but orthodox, majority Mahāsāṃghikas. After unsuccessfully trying to modify the Vinaya, a small group of "elderly members", i.e. sthaviras, broke away from the majority Mahāsāṃghika during the Second Buddhist council, giving rise to the Sthavira sect. Regarding this matter, L. S. Cousins writes, "The Mahāsāṃghikas were essentially a conservative party resisting a reformist attempt to tighten discipline. The likelihood is that they were initially a larger body, representing the mass of the community, the mahāsaṃga."
It seems however that the council, with four representatives from each group, both condemned the lax practices of the Vaisali monks. Therefore the schism did not occur at this time.  Instead it seems the introduction of more rigorous rules was attempted shortly after a second Second Council, where the new interpretation was rejected and led to the 'schism'. 
The Śāriputraparipṛcchā contains an account in which an old monk rearranges and augments the traditional Vinaya, consequently causing dissension among the monks that required the king's arbitration and eventually precipitating the first schism. As stated in the Śāriputraparipṛcchā:
He copied and rearranged our Vinaya, developing and augmenting what Kāśyapa had codified and which was called "Vinaya of the Great Assembly" (Mahāsāṃghavinaya). [...] The king considered that [the doctrines of the two parties represented] were both the work of the Buddha, and since their preferences were not the same, [the monks of the two camps] should not live together. As those who studied the old Vinaya were in the majority, they were called the Mahāsāṃghika; those who studied the new [Vinaya] were in the minority, but they were all Sthaviras; thus they were named Sthavira.
Scholars have generally agreed that the matter of dispute was indeed a matter of vinaya, and have noted that the account of the Mahāsāṃghikas is bolstered by the vinaya texts themselves, as vinayas associated with the Sthaviras do contain more rules than those of the Mahāsāṃghika Vinaya. For example, the Mahāsāṃghika Prātimokṣa has 67 rules in the śaikṣa-dharma section, while the Theravāda version has 75 rules.
According to the Theravadin account, the Second Council occurred in Vaiśālī. Its purpose was to adjudicate on ten points which amounted to minor infringements of the Vinaya, such as handling money and eating after midday. The council was convened, and an elder rendered a verdict condemning the ten points, after which the council was closed. According to this account, some 35 years later at Pāṭaliputra, there was another meeting over five points held by a figure named Mahādeva. These five points were essentially regarding doctrines of the fallibility and imperfection of arhats, which were opposed by some. In this account, the majority (Mahāsaṃgha) sided with Mahādeva, and the minority (Sthaviras) were opposed to it, thus causing a split in the Saṃgha. However, the Samayabhedoparacanacakra records that Mahādeva was a completely different figure who was the founder of the Caitika sect over 200 years later. Some scholars have concluded that an association of "Mahādeva" with the first schism was a later sectarian interpolation. Jan Nattier and Charles Prebish write:
Mahādeva has nothing to do with the primary schism between the Mahāsāṃghikas and Sthaviras, emerging in a historical period considerably later than previously supposed, and taking his place in the sectarian movement by instigating an internal schism within the already existing Mahāsāṃghika school.
Modern scholarship is generally in agreement that the Mahāsāṃghika Vinaya is the oldest. This agrees well with the views of the Chinese monk Faxian, who travelled to India in order to procure the Mahāsāṃghika Vinaya, which was regarded as the original. According to Andrew Skilton, future scholars may determine that a study of the Mahāsāṃghika school will contribute to a better understanding of the early Dharma-Vinaya than the Theravāda school.
According to the traditional Theravadin account, the dispute arose over the 'Ten Points.' This is a reference to claims of some monks breaking ten rules, some of which were considered major. The specific ten points were:
- Storing salt in a horn.
- Eating after midday.
- Eating once and then going again to a village for alms.
- Holding the Uposatha Ceremony with monks dwelling in the same locality.
- Carrying out official acts when the assembly was incomplete.
- Following a certain practice because it was done by one's tutor or teacher.
- Eating sour milk after one had his midday meal.
- Consuming strong drink before it had been fermented.
- Using a rug which was not the proper size.
- Using gold and silver.
The key issue was the use of 'gold and silver', which is an Indic idiom that includes any kind of money. The monks of Vesali had taken to wandering for alms with the specific goal of collecting money, to which the visiting monk Yasa objected. Some of the other points are also important, for example point 6, which would allow monks to not follow the Vinaya on any point which their teacher did not follow or practice.
This behaviour was noted, became an issue and caused a major controversy. The monastic Sangha is structured so that all actions and decisions must be unanimously agreed upon through consensus. Since the monks accused of breaking these ten rules refused to be reprimanded or acknowledge fault, the Sangha was unable to resolve this dispute in any other way than by convening the Second Buddhist Council.
Some of the Ten Points were against minor (dukkata or sekhiya) rules. Before the Buddha's parinibbāna he told Ananda that the community may (unanimously) relinquish the minor rules of the Vinaya but at the First Buddhist Council there was uncertainty about which rules he was referring to and it was unanimously decided to keep the Vinaya as it was during the Buddha's lifetime. However, 100 years later some monks felt that certain rules could be relaxed.
The Second Buddhist Council made the unanimous decision not to relax any of the rules, and censured the behaviour of the monks who were accused of violating the ten points.
- Harvey, Peter (2013). An Introduction to Buddhism: Teachings, History and Practices (2nd ed.). Cambridge, UK: Cambridge University Press. pp. 88–90.
- Skilton, Andrew. A Concise History of Buddhism. 2004. pp. 49, 64
- Harvey, Peter (2013). An Introduction to Buddhism: Teachings, History and Practices (2nd ed.). Cambridge, UK: Cambridge University Press. pp. 89–90.
- Skilton, Andrew. A Concise History of Buddhism. 2004. pp. 49, 64
- Williams, Jane, and Williams, Paul. Buddhism: Critical Concepts in Religious Studies, Volume 2. 2005. p. 190
- Harvey, Peter (2013) p. 89.
- Williams, Jane, and Williams, Paul. Buddhism: Critical Concepts in Religious Studies, Volume 2. 2005. pp. 230–235
- Williams, Jane, and Williams, Paul. Buddhism: Critical Concepts in Religious Studies, Volume 2. 2005. p. 189
- Skilton, Andrew. A Concise History of Buddhism. 2004. p. 48
- Skilton, Andrew. A Concise History of Buddhism. 2004. p. 47
- Sujato, Bhante (2012), Sects & Sectarianism: The Origins of Buddhist Schools, Santipada, p. 78, ISBN 9781921842085
- Walser, Joseph. Nāgārjuna in Context: Mahāyāna Buddhism and Early Indian Culture. 2005. pp. 49–50
- Walser, Joseph. Nāgārjuna in Context: Mahāyāna Buddhism and Early Indian Culture. 2005. p. 50
- Williams, Jane, and Williams, Paul. Buddhism: Critical Concepts in Religious Studies, Volume 2. 2005. p. 188
- Skilton, Andrew. A Concise History of Buddhism. 2004. p. 64
- Bhikkhu Sujato. Sects & Sectarianism: The Origins of Buddhist Schools
- Theravadin account of the Second Council: part 1 and part 2.
- Account of the Second Council from the Mahavamsa