Zou Yan

"[1] His teachings combined and systematized two current theories during the Warring States period: Yin-Yang and the Five Elements/Phases (wood, fire, earth, metal, and water).

It describes him as a polymath (philosopher, historian, politician, naturalist, geographer, astrologer) who came from the coastal state of Qi (present day Shandong), where he was a member of the state-sponsored Jixia Academy.

So he examined deeply into the phenomena of the increase and decrease of the Yin and the Yang, and wrote essays totaling more than 100,000 words about their strange permutations, and about the cycles of the great sages from beginning to end.

He began by classifying China's notable mountains, great rivers and connecting valleys; its birds and beasts; the fruitfulness of its water and soils, and its rare products; and from this extended his survey to what is beyond the seas, and men are unable to observe.

Then starting from the time of the separation of the Heavens and the Earth, and coming down, he made citations of the revolutions and transmutations of the Five Powers (Virtues), arranging them until each found its proper place and was confirmed (by history).