As the legend goes that Fan, the eldest grandson of the six descendants of the 6th generation of Huang Di (the Yellow Emperor) lived in Kunwu, roughly the northeast region of Yuncheng, north China's Shanxi province, and was historically called Kunwu Shi.
In the middle of Xia Dynasty, Di Huai (or Di Fen)gave You Su (today's Su Ling in central China's Henan province) to the offspring of Kunwu Shi as a fief, and they established State Su thereafter.
State Su was perished in late Shang Dynasty, and clansmen of the conquered state took Su as their surname and moved to other places. Only those with surname Su living in Su Ling pledged allegiance to Zhou Dynasty. Su Chasheng secured an official position of Si Kou and King Wu of Zhou Dynasty gave him the place of Su as fief, with capital city in Wen, today's Wen County, Henan province. For this reason, people respectfully called Su Chasheng the earliest ancestor of surname Wen.
During the pre-Qin days (before 221 B.C.), people with surname Su mainly lived in Henan and Hebei. In Warring States period, one branch moved southward to Hunan and Hubei and the other westward to Shaanxi.
During Qin and Han Dynasties, Su people moved eastward to Shandong and later Su people living in the western regions of Shaanxi province became a prominent and distinguished family.
In late Northern and Southern Dynasties, ethnic minorities from northern regions moved to central plains and many changed their surnames to Su during the migration process.
Large number of Su people moved to Sichuang and Fujian during Tang Dynasty. In northern Song Dynasty, they moved further southward to Guizhou, Guangdong and Guangxi.
The Su people moved to Taiwan Island during Ming and Qing Dynasties, and now surname Su on the island has enjoyed the most popularity.
By People's Daily Online