Buddhism arose at a time of significant social and political change. In the regions where it grew and flourished, urban centers were growing rapidly and creating new social conditions. Buddhism — with its egalitarian ideals, its structures for organizing community, and its opportunities for social and religious mobility — was well-suited for the time. With increased trade came a growth in the number of merchants and traders who, even when wealthy and successful, had low social status. Buddhism was appealing because monks were treated equally regardless of their caste. Early texts say that fifty-five of the first sixty of the Buddha's followers were from wealthy and powerful merchant families. Not all monks were wealthy, however; people of any status were welcome.
Regardless of class or economic status, monks had to follow strict rules. A monk could be banished for engaging in sexual relations, stealing, killing someone, or claiming to have supernatural powers. Lesser offenses would lead to a period of probation, the forfeiture of certain privileges, and temporary loss of standing in the community. Monks took vows not to drink alcohol, not to eat after noon, not to indulge in public entertainments, not to use ointments, perfumes, or a comfortable seat or bed, and not to handle money. There were rules against flirting, touching, and masturbation; thirty specific rules about possessions — how one was allowed to acquire and use them; and ninety-two rules that covered miscellaneous offenses such as gossiping or hoarding food. Eventually, all of these rules were recorded in a massive collection of texts, the Vinaya.
When a monk broke a rule, he was required to confess to an assembly of monks, who would then determine and enforce punishment. The assembly would also rule as to whether the acts were intentional or unintentional; monks were normally not punished for unintentional misdeeds. There were additional complex rules of etiquette that served to facilitate harmony within the monastic groups. A well-defined social order eased potential conflicts among those who had grown up with strict caste differentiations and varying rules of social behavior within and between castes.
Women who became nuns were often women who had lost their defined roles in society in some way; they were widows, courtesans, or adult women who had not married. According to the early texts, the first five hundred women to join the sangha were women whose husbands had abandoned them to become monks. The rules for nuns were even more numerous and more stringent than those for the monks. Their status in relationship to the monks was limited in various ways, and they were not permitted to wander alone. Despite this inequity, Buddhist nuns were often less burdened by social restrictions than were women outside the monastic community, and the relative independence and rare opportunity to enjoy spiritual and intellectual pursuits were attractive to some women.
Over time there was some relaxation of the monastic rules. At first all the monks were homeless by choice, except during the monsoon season, and owned few possessions. Originally personal possessions were limited to a robe, a begging bowl, and a staff, but gradually these limits were relaxed. Later some began to settle in monasteries built with gifts of land and money from wealthy lay Buddhists, often built on sites where the monks had stayed during the monsoon season. These monks became more engaged with the lay community, serving as teachers, scholars, doctors, and in other professional capacities. They owned more possessions, most of them collectively, and with time their lives became very comfortable. Other monks continued to follow the old ways, living more isolated and ascetic lives in forested areas.
Lay Buddhists also were given strict rules of behavior. They vowed not to kill, steal, lie, engage in sexual misconduct, or take intoxicants. They were encouraged to be good workers, to take proper care of their possessions, not to overspend or accumulate debt, and to associate with others who shared the same values. They were to fulfill household duties, bring up their children properly, treat their spouses with respect, and take good care of their parents. Through acts of generosity, particularly toward monks, and through lives of virtue and the practice of meditation, lay Buddhists could accumulate merit that could earn them a higher rebirth, perhaps even a rebirth as a monk in a future life.
For the first centuries after Buddha's death, the monastic community was the driving force of the religion. A number of separate monastic groups had already been formed during or just after the Buddha's lifetime. Shortly after his death, a Council composed of the leaders of these groups, as well as prominent disciples of the Buddha, was convened to standardize the doctrine and rules for these communities. A second Council was held a hundred years later to settle further disputes over the rules of discipline.