Lao-tzu cultivated Tao and its virtue. He taught that one should efface oneself and be without fame in the world. He lived under the Chou dynasty. After a long time he realized that the dynasty was declining. He decided to leave. When he reached the western frontier, Yin Hsi, the guardian of the pass, said: "You wan to withdraw forever: Please write down your thoughts for me." Thereupon Lao-tzu wrote a book in two sections dealing with the Tao and its virtue (the Tao-te-ching). It had more than five thousand words. Then he left, and nobody knows what became of him.  --Shih-chi