Wang Xiaotong

Wang Xiaotong (王孝通) (AD 580–640), also known as Wang Hs'iao-t'ung, was a Chinese mathematician, calendarist, politician, and writer of the early Tang dynasty. He is famous as the author of the ''Jigu Suanjing'' (''Continuation of Ancient Mathematics'') one of the ''Ten Computational Canons''.

He presented this work to Li Yuan, the first emperor of the Tang dynasty, along with a brief biography.

According to this autobiography, he became interested in mathematics at a young age. After a study of the ''Nine Chapters on the Mathematical Art'' and particularly Liu Hui's commentary on it, Wang became a teacher of mathematics, and later deputy director of the Astronomical Bureau.

It was known that the Chinese calendar at that time was in need of reform since, although only in operation for a few years, already predictions of eclipses were getting out of step. In 623, together with Zu Xiaosun, a Civil Servant, he was assigned to report on problems with the calendar—although only recently adopted, it was already out of step with the eclipses. In fact, Wang did not approach this in a sophisticated way; he proposed to ignore the irregularity of the sun's motion and also the precession of the equinoxes—both had already been incorporated in calendar calculations by Zu Chongzhi in the fifth century. Provided by Wikipedia