Zhu Xi ([??ú ?í]; Chinese: ??; October 18, 1130 – April 23, 1200), also known by his courtesy name Yuanhui (or Zhonghui), and self-titled Hui'an, was a Chinese calligrapher, historian, philosopher, politician, and writer of the Song dynasty.
He was a Confucian scholar who founded what later became known as the "learning of principle" or "rationalist" school (lixue ??) and was the most influential Neo-Confucian in China.
His contributions to Chinese philosophy including his editing of and commentaries to the Four Books, which later formed the curriculum of the civil service exam in Imperial China from 1313 to 1905; and his emphasis on the process of the "investigation of things" (gewu ??) and meditation as a method for self cultivation.
He has been described by scholar Edward Slingerland as the second most influential thinker in Chinese history, after Confucius himself.He was a scholar with a wide learning in the classics, commentaries, histories and other writings of his predecessors.
In his lifetime he was able to serve multiple times as an government official, although he avoided public office for most of his adult life.
He also wrote, compiled and edited almost a hundred books and corresponded with dozens of other scholars.
He acted as a teacher to groups of students, many who chose to study under him for years.
He built upon the teachings of the Cheng brothers and others; and further developed their metaphysical theories in regards to principle (li ?) and vital force (qi ?).
His followers recorded thousands of his conversations in writing.