 This system was at its height under the yangban aristocracy of the Joseon Dynasty, but it remains in use today.There are approximately 241 such clans claimed by South Koreans.Cheongju Han clan is considered one of the noble clans of Korea, with the Gyeongju Kim, Gimhae Kim, Miryang Park, Gyeongju Seok, Pyeongyang Ko, and Jeonju Lee clans.