Yoon (Korean Name) - Clans

Clans

The Papyeong (파평/坡平) Yoon clan, which has its seat in Papyeong-myeon, Paju City, is the most well-known Yun clan. Several Papyeong Yoon women became queens during the early Joseon Dynasty, and the last ruling Empress, Empress Sunjeong of the Korean Empire, was from another Yoon clan, Haepyeong Yoon. The clan's founding ancestor is General Yun Sin-dal, who assisted Wanggeon in founding the Goryeo Dynasty. The 2000 South Korean census found 221,433 households claiming membership in the Papyeong clan, with a total population of 713,947.

http://en.wikipedia.org/wiki/Empress_Sunjeong "Empress Sunjeong was born Lady Yun of Haepyeong in Seoul and her father was Marquis Yun Taek-yeong, the Lord of Haepung. "