No matter what period they were in, the books that ancient scholars must read must include the "Four Books" and the "Five Classics"
The four books are: Great Learning, Doctrine of the Mean, The Analects of Confucius, and Mencius
The Five Classics are: The Book of Songs, the Book of Documents, the Book of Rites, the Book of Changes, and the Spring and Autumn Period
Of course, they may also read Zhu Xi's "Commentary on Chapters and Sentences of the Four Books" or Wang Yangming, Wang Fuzhi, Neo-Confucianism of the Song and Ming Dynasties, Ercheng, Historical Records, etc.
These are the books most read by ancient scholars