The Yellow Emperor or Huang Di is a legendary Chinese sovereign and cultural hero who is said to be the ancestor of all Han Chinese.
One of the Five Emperors, the Yellow Emperor is said by tradition to have reigned from 2698 BCE to 2599 BCE. The legend of his retreat to west in the war against the eastern Emperor Chi You at the Battle of Zhuolu is seen as the establishment of the Han Chinese nationality.
According to legend, the Yellow Emperor invented the earliest form of the Chinese calendar, and its current sexagenary cycles are counted based on his reign. Among his other accomplishments, the Yellow Emperor has been credited with the invention of the principles of Traditional Chinese Medicine.