Who he was
Ji Chang, King Wen (文王, "the cultured king"), led the Zhou people in the 11th century BCE, while they were still vassals of the Shang. His son, King Wu, overthrew the Shang and founded the Zhou dynasty.
What tradition says
The story goes that the last Shang king held him prisoner at Youli, and that in captivity he doubled the eight trigram figures into the 64 hexagrams and wrote each one's judgment. Tradition gives the line texts to his son, the Duke of Zhou. Even the old sources are careful: the historian Sima Qian tells it with a "probably," and the Great Commentary only asks whether the book arose in King Wen's time, without saying so.
What historians think
There's no evidence King Wen wrote any of the book. Many scholars see the Zhouyi as a work gathered by diviners over generations. The attribution says more about how revered the text was than about who wrote it.
Where you'll see his name
- The King Wen sequence, the order in which the 64 are read.
- The Later Heaven arrangement of the trigrams, linked to him by Song dynasty thinkers.
Along with Fu Xi and Confucius, he's one of the three sages that tradition places at the origin of the I Ching.