Laozi is the name of a legendary Daoist philosopher, the alternate title of the early Chinese text better known in the West as the Daodejing, and the moniker of a deity in the pantheon of organized "religious Daoism" that arose during the later Han dynasty (25-220 CE). Laozi is the pinyin Romanization for the Chinese characters which mean "Old Master." Laozi is also known as Lao Tan ("Old Tan") in early Chinese sources (see Romanization systems for Chinese terms). The Zhuangzi is the first text to use Laozi as a personal name and to identify Laozi and Lao Tan. The earliest materials associated with Laozi are in the Zhuangzi's Inner Chapters. The Outer Chapters of that work have ten logia in which Laozi is the main figure, four of which contain direct attacks on the Confucian virtues of ren, yi, and li that are reminiscent of passages from the Daodejing and probably date from the period in which that collection was reaching some near final form. The earliest ascription of authorship of the Daodejing to Laozi is in Han Feizi and the Huainanzi, but several themes from the Laozi logia of the Zhuangzi are traceable into the Daodejing and on at least two occasions in that text Laozi counsels following dao (the Way) to possess de (virtue). Laozi became a principal figure in institutionalized religious forms of Daoism. He was often associated with many transformations and incarnations of the dao itself.
Most later writings about Laozi continued to base their appeals to Laozi's authority on his ongoing transmigrations, but they give evidence of the growing tension between Daoism and Buddhism. The first mythological account of Laozi's birth is in the Scripture of the Inner Explanation of the Three Heavens, a Celestial Master work dated about 420 CE. In this text, Laozi has three births: as the manifestation of the dao from pure energy to become a deity in heaven; in human form as the ancient philosopher of the Daodejing; and as the Buddha after his journey to the West. In the first birth, his mother is known as The Jade Maiden of Mystery and Wonder. In his second, he is born to a human woman known as Mother Li. This was an eighty-one year pregnancy, after which he was born from her left armpit (there is a tradition that Buddha had been born from his mother's right arm pit). At birth he had white hair and so he was called laozi (Old Child). This birth is set in the time of the Shang dynasty, several centuries before the date Sima Qian reports. But the purpose of such a move is to allow him time to travel to the West and then become the Buddha. The third birth takes place in India as the Buddha. For details of this birth we turn to Esoteric Record of Mystery and Wonder, another fifth century document of the Celestial Masters. According to this text, Laozi entered into the body of the wife of the king of India through her mouth. Later he was born through her left arm pit. He walked immediately after his birth, and "from then on Buddhist teaching came to flourish." (quoted in Kohn)