Zhou Dunyi
Zhou Dunyi (; 1017–1073) was a Chinese cosmologist, philosopher, and writer during the Song Dynasty. He conceptualized the Neo-Confucian cosmology of the day, explaining the relationship between human conduct and universal forces. In this way, he emphasizes that humans can master their "qi" ("vital life energy") in order to accord with nature. He was a major influence to Zhu Xi, who was the architect of Neo-Confucianism. Zhou Dunyi was mainly concerned with Taiji (supreme polarity) and Wuji (limitless potential), the yin and yang, and the wu xing (the five phases). He is also venerated and credited in Taoism as the first philosopher to popularize the concept of the taijitu or "yin-yang symbol".