Yeh-lü Ch'u-ts'ai (1189-1243), secretary-astrologer to Genghis Khan and chief of the Secretariat under his son Ögödei, was famous for his administrative reforms introduced in North China during the early years of the Mongol conquest.

The son of a Sinicized Khitan noble serving the Jürchen-Chin dynasty (1115-1234), Yeh-lü Ch'uts'ai was born in the Chin capital Chung-tu (modern Peking). He began the study of Chinese classics at the age of 12. Placing first in the degree examination, he was appointed a district vice-prefect in modern Hopei (1213); when the Chin emperor transferred his court to Pien-ching (K'ai-feng) in 1214, Yeh-lü returned to the old capital to become an auxiliary secretary in the Secretariat Council. He stayed to witness the fall of Peking to the Mongol forces in 1215.

Meanwhile, Yeh-lü had developed an interest in Buddhism and lived in seclusion as a lay disciple until...