As far as I know, Han (Korean) is the oldest surname recorded in Korean history. The first ancestor of Han migrated from China to Korea and organized a kingdom called Gi-Ja Chosen around BC 1171. There are two theories about Han's nationality, Chinese or Korean. It seems that in ancient times, Koreans ruled in the main land China. Being in the land presently called China, some people call them (Han's ancestors) Chinese. It's just history. As you know history is always for the winners. Who knows what.