Not much is known about Lao Tzu, at least nothing that is certain. Some even doubt whether he is the author of the Tao Te Ching. However, his name became legendary with this writing, which also happens to be his only work.
Lao Tzu (his name is sometimes written Lao Tse or Lao Zi, and he is also known as Li Er and Lao Dan) was supposedly born in Honan on the 24th of March in the year 604 BC. His name means “old-young” and he has been called the “Old Master”.
Lao Tzu was very old, when he rode on a water buffalo to retire in the mountains to a province in the western frontiers. There he was approached by a border official named Guan Yin Zi, who urged the master to write down his teachings so that they might be passed on.
Lao Tzu then retreated into the solitude of the mountain pass, wrote the Tao Te Ching, whereupon he went westward and was never seen again.
text credits :http://www.thebigview.com/tao-te-ching/index.html