According to Chinese tradition, filial piety was the primary duty of all Chinese. Being a filial son meant complete obedience to one's parents during their lifetime and--as they grew older--taking the best possible care of them. After their death the eldest son was required to perform ritual sacrifices at their grave site or in the ancestral temple. A son could also express his devotion to his parents by passing the Civil Service examinations, winning prestige for the whole family. Most important of all, a son had to make sure that the family line would be continued. Dying without a son therefore was one of the worst offenses against the concept of filial piety. If a marriage remained barren, it was a son's duty to take a second wife or adopt a child in order to continue the family. Since Chinese women became part of their husband's family through marriage, filial conduct for a woman meant faithfully serving her in-laws, in particular her mother-in-law, and giving birth to a son. By fulfilling these duties, she also gained prestige for her own family. If the mother and daughter-in-law did not get along, filial piety demanded that a man should get rid of his wife in order to please his mother. He could always get another wife, but he would only have one mother. While continuing the family line was probably the most important issue for the vast majority of the Chinese, Buddhist monks and nuns were required to remain celibate. Their refusal to fulfill the obligations of filial piety made them suspect in the eyes of other Chinese. Along with the eunuchs at the emperor's court and Taoist priests they were often believed to conduct themselves in an immoral or criminal manner.