Lǐ Rúsōng was a Ming general who led Chinese forces in helping to expel Toyotomi Hideyoshi's forces from Korea during the First Korean Invasions in 1592.
Rusong was the son of Li Chengliang (1526-1615), an official of presumably Korean-Jurchen background, who held a hereditary post in the area of the Liaodong peninsula, which his ancestors had held for some generations. Chengliang is also known to have fought for the Ming in a number of notable campaigns, chiefly against the Jurchens.
Three lineages of Rusong's descendants became subjects of the Joseon Dynasty Korean court, and fought for a time under Korean banners against the Manchu forces of Nurhachi. Coming to be known as the Nongsŏ Yi lineage, they became a relatively prominent lineage of Ming descendants within Joseon Korea. Originally known as hyang hwain, or "submitting-foreigners," a term with the connotation of people who came to Korea as a civilizational center, to become more civilized, more cultured, i.e. "morally transformed," a rhetoric and ideology adapted from the Chinese by the Koreans, beginning in the 1750s or so, Ming descendants including the Nongsŏ Yi were re-classified as hwang join, or "imperial subjects," acknowledging them as remnants of the Great Ming. Among the Nongsŏ Yi, some claimed descent from Rusong's brother Li Rumei, some from Rusong's second son Li Xingzhong, and some from a supposed affair between Li Rusong and a Korean woman, the child of this union having established himself originally on Goeje Island. There are still people today in South Korea who claim descent from the Nongsŏ Yi, claiming too membership in a broader Sŏngju Yi lineage, which like many Korean yangban (scholar-official) lineages, claims descent from a prominent Koryo Dynasty official, and through him to a prominent figure of the Silla Kingdom.
Meanwhile, Li Chengliang's descendants who remained under the Qing Dynasty became classified as either members of the Manchu or "martial Chinese" (hanjun) banners, a nice example of how constructed and changeable ethnic identity can be.
References
- Bohnet, Adam. “Ruling Ideology and Marginal Subjects: Ming Loyalism and Foreign Lineages in Late Chosŏn Korea.” Journal of Early Modern History 15, no. 6 (January 1, 2011): 499.