What was the origin of Zhongshan during the Spring and Autumn Period and the Warring States Period?

A small vassal state in the Spring and Autumn Period and the Warring States Period was called Zhongshan State (Pingshan County, Shijiazhuang, Hebei Province);

The predecessor of Sun Yat-sen State is the Xianyu tribe of Bai Di, a northern minority. First in Suide area of northern Shaanxi, it gradually moved to Taihang Mountain area. Ji's surname is the surname of the Zhou royal family, and its origin is said to be the descendant of Bi Wangong, and it is also said to belong to Xi Guo, which was addressed to his younger brother Guo Shu. The kings of the Western States served as Qing people in the Zhou Dynasty, and at the same time they were one of the three public officials, who were responsible for fighting in the north and fighting in the east to punish the imperial court. It may be that during the period, King Xi Guo was the emperor ruler of the north, and some of his descendants stayed in northern Shaanxi after passing through the Su River and Yu River in Salou, Inner Mongolia. Xianyu, named after Xianyu Water, is a Qingshui River that flows from the southwest of Wutai Mountain to the Hutuo River. This area is the earliest birthplace of Xianyu. Xianyu's name first appeared in the book Mandarin. According to the records in the book, in eight years (774 BC), when Taishbo answered questions, he said that there were six vassal states named Ji 16 in the northwest, as well as countries or tribal groups such as Na Man, Dong Yi, Rong and Di, among which there were fresh dangers.