enforced. This was a period of unrest, and the state promoted the practice of long-term mourning to reestablish their authority. Filial piety toward one's parents was expected to lead to loyalty to the ruler, expressed in the Han proverb "The Emperor rules all-under-heaven with filial piety". Government officials were expected to take leave for a mourning period of two years after their parents died. Local officials were expected to encourage filial piety to one's parentsand by extension, to the stateby behaving as an example of such piety. Indeed, the king himself would perform an exemplary role in expressing filial piety, through the ritual of "serving the elderly" (). Nearly all Han emperors had the word xiào in their temple name. The promotion of filial piety in this manner, as part of the idea of li, was more an acceptable way to create order in society than resorting to law. Filial piety became a keystone of Han morality. During the early Confucian period, the principles of filial piety were brought back by Japanese and Korean students to their respective homelands, where they became central to the education system. In Japan, rulers gave awards to people deemed to practice exemplary filial conduct. During the Mongolian rule in the Yuan dynasty (13th14th century), the practice of filial piety was perceived to deteriorate. In the Ming dynasty (14th17th century), emperors and literati attempted to revive the customs of filial piety, though in that process, filial piety was reinterpreted, as rules and rituals were modified. Even on the grassroots level a revival was seen, as societies that provided vigilance against criminals started to promote Confucian values. A book that was composed by members of this movement was The Twenty-four Cases of Filial Piety. Introduction of Buddhism Filial piety is an important aspect of Buddhist ethics since early Buddhism, and was essential in the apologetics and texts of Chinese Buddhism. In the Early Buddhist Texts such as the Nikāyas and Āgamas, filial piety is prescribed and practiced in three ways: to repay the gratitude toward one's parents; as a good karma or merit; and as a way to contribute to and sustain the social order. In Buddhist scriptures, narratives are given of the Buddha and his disciples practicing filial piety toward their parents, based on the qualities of gratitude and reciprocity. Initially, scholars of Buddhism like Kenneth Ch'en saw Buddhist teachings on filial piety as a