From Mencius in the Spring and Autumn Period.
Mencius is a Confucian classic written by Mencius and his disciples Zhang Wan and Gongsun Chou in the middle of the Warring States Period. It was first seen in Zhao Qi's inscription "Mencius": "This book was also written by Mencius, so it is called Mencius". Mencius was listed as "Four Books" by Zhu in the Southern Song Dynasty (the other three books were Daxue, The Doctrine of the Mean and The Analects of Confucius).