Pi xie lun (Refuting heresy) is by Yang Guangxian (1597–1669) from Shexian, Anhui Province, a fierce opponent of the early Christian missionaries to China. Beginning about 1659, Yang assumed the self-appointed role of campaigner against the missionaries. In 1644, German Jesuit Johann Adam Schall von Bell (circa 1592–1666) was asked to prepare for the new Qing dynasty a calendar based on Western mathematical calculations. Schall later was named director of the imperial Board of Astronomy. Yang submitted a document to the Board of Ceremonies, charging Schall with errors ...