Laozi is revered as the Patriarch of Taoism. According to the "Records of the Grand Historian" by Sima Qian of the Western Han Dynasty, Laozi's surname was Li, his given name was Er, and his courtesy name was Dan. He was from Qurenli, Lixiang, Ku County, the State of Chu. The "Biographies of Immortals" written by Liu Xiang of the Western Han Dynasty states that Laozi's courtesy name was Boyang and he was from the State of Chen. Taoism holds that both "Dan" and "Boyang" are the characters of Laozi. As for its native place, it either belonged to the State of Chen or to the State of Chu. These two claims do not conflict. Ku County originally belonged to the State of Chen, but later the State of Chen was conquered by the State of Chu, so Ku County also belonged to the State of Chu. The "Records of the Grand Historian" does not record the year of Laozi's birth, only stating that Confucius once asked him for respect. The "Biographies of Immortals" records that Laozi was born in the Yin Dynasty. According to Taoist classics, Laozi served as the Secretary of the Treasury during the reign of King Wen of Zhou and later moved to the position of Secretary of the Pillar. When the Zhou Dynasty was in decline, Laozi resigned from his official position and left. When passing through the Hangu Pass (now in Lingbao County, Henan Province), the pass magistrate Yin Xi earnestly requested him to write a book to be passed down through the ages. Thus, Laozi wrote over five thousand words, which is the "Tao Te Ching" that has been passed down through the ages. During the Pre-Qin period, successive figures such as Yinzi (Yin Xi), Yang Zhu, Liezi, and Zhuangzi inherited and developed Laozi's thoughts, thus forming the Daoist school. At the end of the Warring States Period, Taoism associated Laozi with the Yellow Emperor, thus forming the School of Huang-Laozi. In the early Western Han Dynasty, the philosophy of Huang-Lao was once regarded as the guiding ideology in politics. During the Han Dynasty, the thought of tranquility and non-action in the Huang-Lao School combined with the belief in immortals in the Fang-Xian School, giving rise to the Huang-Lao School, in which Laozi was regarded as the embodiment of the "Dao". During the reigns of Emperor Ming and Emperor Zhang of the Eastern Han Dynasty, Wang Fu, the governor of Yizhou, composed the "Laozi Holy Mother Stele", which reads: "Laozi is the way." In the eighth year of the reign of Emperor Huan's Yanxi (165 AD), Minister Chen Bian Shao composed the "Epitaph of Laozi", praising Laozi as "having achieved enlightenment and immortality, and having transformed into a cicada to cross the world." Since Fu Xi (God) Nong, I have been the teacher of the sage for all ages. During the reign of Emperor Shun of the Eastern Han Dynasty, Zhang Daoling founded the Zhengyi Alliance Wei Dao (also known as the Heavenly Master Dao) on the Heming Mountain in Sichuan and Chongqing. He revered Laozi as the leader of the sect and regarded "Dao" as the highest faith, adhering to the "Five Thousand Texts of Laozi" as the classic. Zhang Daoling also wrote the "Commentary on Laozi Xiang 'er", which holds that the Dao, when dispersed, forms qi, and when gathered, forms the Supreme Laozi (i.e., Laozi). Later, Taoism revered Laozi as the "Heavenly Lord of Morality" and listed him as one of the Three Pure Deities. In Taoism, there is also a saying that "Laozi transforms the qi into the three pure ones." The emperor of the Tang Dynasty, surnamed Li, claimed to be a descendant of Laozi and revered Laozi as the sage ancestor. In the first year of the reign of Emperor Gaozong of Tang (666), Laozi was honored as the "Supreme Xuanyuan Emperor". Subsequently, during the Tianbao period, Emperor Xuanzong repeatedly added the titles of "Great Sage Ancestor Xuanyuan Emperor", "Great Sage Ancestor Daodao Xuanyuan Emperor", and "Great Sage Ancestor Gaoshang Jinque Xuanyuan Emperor", and established the Taiqing Palace in the Western capital and Bozhou. To avoid the taboo of Zhao Xuanlang, the founding emperor of the Song Dynasty, Emperor Zhenzong of the Song Dynasty renamed Laozi "Emperor Zhenyuan". In the eighth month of the sixth year of the Xiangfu reign of the Dazhong Dynasty (1013), an imperial edict was issued to add the title of Laozi to "Supreme Elder Lord Hunyuan Shangde Emperor". In the third year of Kaiyuan (715), Emperor Xuanzong of Tang issued an imperial edict designating the 15th day of the second lunar month, the birthday of Laozi, as the Xuanyuan Festival. Later, Emperor Wuzong of Tang ordered Laozi's birthday to be designated as the Day of the Descent of the Sage, with a one-day national holiday. It can be seen that Laozi's birthday falls on the 15th day of the second lunar month, which was once confirmed by the Tang government and regarded as a public holiday.