For much of the imperial period the Mencius was one venerable text among many, but in the Song dynasty the great Neo-Confucian Zhu Xi (1130-1200) singled it out, together with the Analects, the Great Learning and the Doctrine of the Mean, as one of the Four Books, the essential core of the Confucian curriculum, to be studied before the older Five Classics.
Through Zhu Xi's commentaries the Four Books, and with them Mencius's doctrine of innate goodness, became the foundation of Chinese education and, from the fourteenth century until the examination system was abolished in 1905, the basis of the civil service examinations on which official careers depended. Mencius's optimistic view of human nature became, in this way, something close to the orthodox anthropology of later Confucian civilisation across China, Korea, Japan and Vietnam, though it was always contested, most sharply by Xunzi, who held that human nature is bad and virtue the achievement of deliberate effort. Today the Mencius remains a foundational text of the Confucian tradition and a classic of world philosophy.