China even today. The Letter to Ren An contains the quote, "Men have always had but one death. For some it is as weighty as Mount Tai; for others it is as insignificant as a goose down. The difference is what they use it for." (人固有一死，或重于泰山，或輕于鴻毛，用之所趨異也。) This quote has become one of the most well known in all of Chinese literature. In modern times, Chairman Mao paraphrased this quote in a speech in which he paid tribute to a fallen PLA soldier. Sima Qian wrote eight rhapsodies (fu), which are listed in the bibliographic treatise of the Book of Han. All but one, the "Rhapsody in Lament for Gentlemen who do not Meet their Time" (士不遇賦) have been lost, and even the surviving example is probably not complete. Astronomer/astrologer Sima and his father both served as the taishi (太史) of the Former Han Dynasty, a position which includes aspects of being a historian, a court scribe, calendarist, and court astronomer/astrologer. At that time, the astrologer had an important role, responsible for interpreting and predicting the course of government according to the influence of the Sun, Moon, and stars, as well as other astronomical and geological phenomena such as solar eclipses and earthquakes, which depended on revising and upholding an accurate calendar. Before compiling Shiji, Sima Qian was involved in the creation of the 104 BC Taichu Calendar 太初暦 (太初 became the new era name for Emperor Wu and means "supreme beginning"), a modification of the Qin calendar. This is the first Chinese calendar whose full method of calculation (暦法) has been preserved. The minor planet "12620 Simaqian" is named in his honour. Family Sima Qian is the son of court astrologer (太史令) Sima Tan, who is a descendant of Qin general Sima Cuo (司馬錯), the commander of Qin army in the state's conquest of Ba and Shu. Before his castration, Sima Qian was recorded to have two sons and a daughter. While little is recorded of his sons, his daughter later married Yang Chang (楊敞), and had sons Yang Zhong (楊忠) and Yang Yun (楊惲). It was Yang Yun who hid his grandfather's great work, and decided to release it during the reign of Emperor Xuan. Unsubstantiated descendants According to local legend, Sima Qian had two sons, the older named Sima Lin (司馬臨) and younger named Sima Guan (司馬觀), who fled the capital to Xu Village (徐村) in what is