Beiming, a rare double surname, is a very mysterious family and one of the original four major families (Dongfang, Nangong, Ximen and Beiming).
Originating from the Spring and Autumn Period, it was at its peak during the Warring States Period. At its largest, his family only had more than 200 people.
When the Qin Dynasty unified the six kingdoms, everyone in the family had their own ambitions. Then the patriarch Beiming Yiqian passed away and the family was in chaos. Killings of each other, foreign tribes taking advantage of the situation, and vassal states' expropriation reduced the direct lineage of Beiming for a time. In order to preserve the ethnic group, the direct lineage system was forced to conceal their original surnames. Some were named Zhang (mostly distributed in Shandong Peninsula, Henan and Hebei), some were named Li (distribution unknown), and some were named Zheng (mostly distributed in Shanxi) and disappeared overnight. When Bei Ming was in danger of death, most of the Bei Ming Wai Department broke away from Bei Ming and established their own school, calling themselves Beitang.
(This story is purely fictional! Please forgive me for any inconsistencies with history, which I will try my best to avoid. In addition, I changed the starting time of the story to the beginning of Qin Dynasty. Please forgive me)