Four books refer to four works: The Great Learning, The Doctrine of the Mean, The Analects of Confucius and Mencius. Among them, The Analects of Confucius and Mencius are collections of speeches by Confucius, Mencius and their students respectively, while Daxue and The Doctrine of the Mean are two books in The Book of Rites. Zhu, a famous scholar in the Southern Song Dynasty, first linked the two.
The Five Classics refers to five works: The Book of Songs, Shangshu, Book of Rites, Zhouyi and Chunqiu. The name of the Five Classics began with Emperor Wu of the Han Dynasty. On this basis, the Eastern Han Dynasty added The Analects of Confucius, The Book of Filial Piety and The Seven Classics.