Won surname is the monarch of Xu in the Western Zhou Dynasty in China history. During his reign, Xu was very powerful, and his territory extended to Jiangsu, Anhui, north of the Yangtze River and southern Shandong. Biographies of the Eastern Han Dynasty: "The place is 500 Li", paying tribute to him "There are six countries in thirty".

During Xu Yanwang's reign, he was benevolent and won the support of the people. During this period, 32 countries around Xu paid tribute to Xu. After the national strength became strong, Xu Yanwang attacked the capital of Zhou Dynasty on a large scale, forcing Zhou Muwang to "divide Dongwu vassals into Xu Yanwang". After a personal expedition, he defeated Xu with the help of Chu's military strength. Since then, Xu Yanwang has lived in seclusion in the mountains around Pengcheng (now Xuzhou, Jiangsu) (killed by Zhou Jun). Buried in Dongqian Lake, Yin County. Name his descendants and continue to rule Xu.

Xu was one of the vassal states in the Spring and Autumn Period of the Western Zhou Dynasty, and the monarch was named Won. Xu Rong, also known as Xu Yi or Xu Fang, is a member of Dongyi Group. From Xia Dynasty to Zhou Dynasty, it was distributed in the present Tancheng area of Shandong Province. Only in Zhou Muwang's time did he submit to the Zhou Dynasty. At the beginning of the Zhou Dynasty, Xu State was established with Sixian County in Anhui Province and Sihong in Jiangsu Province as the center, which was the most powerful in Dongyi. It was defeated by Chu in the Spring and Autumn Period and destroyed by Wu in 5 12.