Lao Tzu

Lao-tzu was a native of Ch'ü-jen, a village in the state of Ch'u, which corresponds to the modern Lu-yi in the eastern part of Honan Province. 
He was appointed to the office of shih at the royal court of the Chou dynasty (c. 1111-255 BC). Though shih means "historian," in ancient China the shih were scholars specializing in matters such as astrology and divination and in charge of sacred books.

Next the historian proceeds to relate a celebrated but questionable meeting of old Tzu with a younger Confucius (551-479 BC). The story has been much discussed by the scholars; it is mentioned elsewhere, but the sources are so inconsistent and contradictory that the meeting seems a mere legend. During the supposed interview, Lao-tzu blamed Confucius for his pride and ambition, and Confucius was so impressed with Lao-tzu that he compared him to a dragon that rises to the sky, riding on the winds and clouds. 

in this painting, confucius presents prince gautama (buddha) to lao tzu 

No less legendary is a voyage of Lao-tzu to the west. Realizing that the Chou dynasty was on the decline, the philosopher departed and came to the Hsien-ku pass, which was the entrance to the state of Ch'in. 

did lao tzu really leave for the west in a water buffalo?

Yin Hsi, the legendary guardian of the pass (kuan-ling), begged him to write a book for him. Thereupon, Lao-tzu wrote a book in two sections of 5,000 characters, in which he set down his ideas about the Tao (the Supreme Principle) and te (virtue): the Tao-te Ching. 

The question of whether there was a historical Lao-tzu has been raised by many scholars, but it is rather an idle one. The Tao-te Ching, as we have it, cannot be the work of a single man; some of its sayings may date from the time of Confucius; others are certainly later; and the book as a whole dates from about 300 BC. Perhaps the name Lao-tzu seems to represent a certain type of sage rather than an individual.