Emperor Xiaowu of the Song dynasty assigned him to the Hualin academy. He also gave him a residence a chariot and clothing. Zu Chongzhi is best known for revising the calendar. His revision was based on a new estimate of the length of the year, an estimate that was accurate to 50 seconds. A court of rival accused him of ‘distorting the truth about heaven and violating the teaching of the classics.’
Zu Chongzhi was a very capable geometer and astronomer. He was one of the greatest mathematicians of ancient China. He computed π to be 355/113 a value not bettered until 1000 years later by al-Kashi (1430).
In astronomy he measured the length of the year to be 365.2429 days, by extensive observations of the length of shadows around the winter solstice, and improvement over contemporary values.
Around 494, Zu Chongzhi was appointed commandant of Changshui which put him in charge of the border area.
He wrote ‘An bian Lun’ (Disquisition on securing the frontier). He also expanded the military farms in the border region, which resulted in increased agricultural production.
Zu Chongzhi – Chinese mathematician and astronomer
