The surname source of Nanmen surname.

Originated from astronomical phenomena, from ancient celestial officials, named after astronomical constellations. According to the historical book "Historical Records and Official Records", there are two big stars in the sky, called Nanmenxing. In modern astronomy, they refer to the two stars in the southern sky, Compass and Centauri, respectively. They are the closest stars to the earth. Nanmen's family originated from the descendants of ancient officials in charge of observing astronomy. In ancient myths and legends of China, the gatekeeper guarding the worse gate was the first orthodox god in the sky. The worse gate is the gateway for all gods, monsters, ghosts, demons and demons to enter and leave by the imperial decree of heaven. The worse weapon of God is two swords, green and white, with one of the nine sons of Longsheng attached to them. Yazi looks like a dragon head, strong-willed, killing and fighting. Whenever the worse god brandishes his sword, it is like holding two giant pythons in each hand, one green and one white, he is always majestic. Later, people learned from the worse god of heaven, and also carved satchels on the knife ring, the throat of the handle or the scabbard of the handle.

The surname "South Gate" probably comes from the descendants of ancient officials in charge of astronomical observation. Named South Gate after the South Gate constellation. Later, many provinces changed to south gate and stores, which were passed down from generation to generation. Originated from the surname of Zi, it is the descendant of Nan Jiaomen, the minister of Shang Dynasty, and belongs to the surname of ancestors or official positions. According to legend, in the early Shang Dynasty, Tang Cheng had an important minister named Nanmenxiang. In the classic Xunzi, it is mentioned that the ancestor of Nanmenshi is Nanmenxiang. At the beginning of the establishment of Shang Tang, the Tang King had seven ministers, namely: Qingfu, Yi Yin, Huang Liqi, Dongmenxu, Nanmenxu, Ximenxiu and Beimenxu, among which Nanmenxu was one of the seven ministers. This book holds that the functions of the four ministers, East Gate Preface, South Gate Preface, Ximenpi and Beimenbian, are not only as simple as guarding Wang Chengmen Guo, but are probably the supreme commanders of the armed forces in all directions and regions. Otherwise, these four small customers will not be listed as "important ministers". Therefore, the south guard should be understood as the highest military and political chief in charge of the southern region of the Shang Dynasty.

Among the descendants of Nanmen Township, there are people who take their ancestors' names or official titles as surnames, which are called Nanmen's, which is one of the very old surnames. Later, many provincial names were changed to Heather and Menshi, which were handed down from generation to generation. Most people in Nanmen clan respect Nanmen Creek as the ancestor of their surname. Originated from the official position, the official who guarded the south gate of the town during the Zhou Dynasty belongs to the official title. Zhang Shu, a famous scholar of surnames in Qing Dynasty, said in his book Searching for Surnames: "People who must live in the South Gate think of their surnames, or officials who open and close the South Gate think of their surnames." It means that the ancestors of the Menshi clan must have lived in the south gate of the city wall in ancient times, or were officials and soldiers guarding the south gate of the city, so they were named Nanmen clan in the name of Juyi or in the name of official title. Later, because the south gate was the meridian gate, emperors used it to slay guilty ministers, which was called the gate of blood and fire, which was unlucky. Therefore, most of the bamboo slips in Nanmen Province were changed to heather and store names, which were passed down from generation to generation.

It should be noted that the official title of "South Gate" has not been seen in Tong Dian Zhi Guan written by Du You, a scholar in the Tang Dynasty, and it has been the same since then. Originated from the surname Ji, the residents living near the south gate of the city in the Zhou Dynasty belonged to the surname of residence. It is mentioned in the classic Xunzi that the ancestor of the South Gate is the South Gate Creep. Many scholars believe that residents living near the south gate of the city also take the name of their place of residence as their surname, also known as the south gate. Later, the vast majority of people with compound surnames in Nanmen gradually simplified and changed to single surnames in Nanmen.