In the Canon of Yao, the first chapter of the Book of Documents, Yao asks the Four Mountains, his chief ministers: “I have been on the throne seventy years. Can you carry out the mandate and take my place?” They answer: “Our virtue is too poor. We would disgrace the throne.” Yao says: “Bring forward the illustrious, and raise up the humble too.”
The assembly then tells him: “There is an unmarried man in a low station, named Shun of Yu.” Yao says: “I will test him.”