He is said to have fled to Chaoxian (朝鮮, Joseon in Korean) when Shang was overthrown by Zhou. He established the dukedom of Chaoxian and it was granted by King Wu of Zhou. This story was first appeared in the Records of the Great Historian by Sima Qian. Slightly more detailed ones were recorded in Hanshu[?] and Weilue[?]. The dukedom is called Jizi Chaoxian (Gija Joseon) today.
Commanderies and kingdoms controlling northern Korea were regarded as successors of Jizi by the Chinese and Koreans. The Koreans, especially Confucians, considered the legend as a historical fact and felt proud of being successors of the sage. King Sukjong of Goryeo[?] identified a mound near P'yongyang as Jizi's tomb. He built a mausoleum to enshrine him in 1102. The name of the Joseon Dynasty[?], given by Ming, was derived from Jizi's dukedom.
wikipedia.org dumped 2003-03-17 with terodump