The traditional account: an archivist of the Zhou court who, disillusioned with its decline, rode west on a water buffalo. At the pass, the gatekeeper asked him to leave behind his wisdom before crossing into obscurity. He wrote the Tao Te Ching — five thousand characters — and vanished.
Modern scholarship doubts a single author; the text was likely compiled and layered over centuries. Either way the work has acted as a person — the voice whom Chinese tradition calls Laozi, the Old Master.