A Chinese astrologer and historian of the 2nd century BC, Sima Tan served as Grand Astrologer at the Han court. He undertook the writing of the *Shiji* (Records of the Grand Historian), a work his son Sima Qian completed after his death.
Sima Tan(164 av. J.-C. — 109 av. J.-C.)
Sima Tan
Han de l'Ouest
8 min read
Frequently asked questions
Key Facts
- Born around 165 BC, died around 110 BC
- Appointed Grand Astrologer (Taishi Ling) at the court of Emperor Han Wudi
- Initiated the writing of the *Shiji* (Records of the Grand Historian), China's first great universal history
- His son Sima Qian completed the *Shiji* after his death, around 91 BC
- Wrote an essay classifying the six philosophical schools of thought in China of his time
Works & Achievements
Sima Tan conceived and began writing this monumental work of 130 chapters covering more than 2,000 years of Chinese history. He defined its structure in five sections (imperial annals, chronological tables, treatises, hereditary houses, biographies) and gathered the sources before entrusting its completion to his son Sima Qian, who brought the project to fruition around 90 BCE.
The only text attributed entirely to Sima Tan, preserved in the postface of the Shiji, it analyzes the six major Chinese philosophical schools and concludes that Taoism holds a superior, synthetic position among them. It is a major philosophical document of the Han period, remarkable for its comparative approach, which was rare for the time.
As Grand Astrologer, Sima Tan oversaw official celestial observations and the preparatory calculations for the calendar reform, which his son completed in 104 BCE. This scientific work, passed on to Sima Qian, forms the astronomical dimension of the Shiji.
Anecdotes
On his deathbed in 110 BC, Sima Tan took his son Sima Qian's hands in tears. He entrusted him with his most precious mission: to complete the Records of the Grand Historian that he had been unable to finish. “If you become Grand Historian after me, do not forget what I wished to write,” he told him. Sima Qian himself recounts this deeply moving scene in the postface of the Shiji.
Sima Tan was one of the rare scholars of his time to master astronomy, divination, and philosophy alike. He studied the stars under the renowned astronomer Tang Du, received training in the Yi Jing (Book of Changes) under the master Yang He, and deepened his knowledge of Taoist thought under Huang Shengong. This triple expertise earned him an appointment as Grand Astrologer at the court of Emperor Wu of Han.
Sima Tan was an original thinker who analyzed and compared the six major philosophical schools of ancient China: Confucianism, Taoism, Mohism, Legalism, the School of Names, and the School of Yin-Yang. In his essay preserved in the Shiji, he concluded that Taoism was the most synthetic of all these schools of thought, as it allowed one to act in harmony with nature. It is one of the few texts directly attributable to his own hand.
In 110 BC, Emperor Wu of Han organized the solemn Feng Shan ceremonies on Mount Tai, the first such rites in centuries. Sima Tan, gravely ill, was unable to attend — a terrible blow for a Grand Astrologer whose very role was to oversee the imperial rituals connected to Heaven. The grief of having missed this cosmic event of the utmost importance is said to have hastened his death that same year.
Primary Sources
My father took my hand and said, weeping: 'Our ancestors served as Grand Historian under the Zhou… If I die, you will surely become Grand Historian in your turn. In that office, do not forget what I wished to write.'
Taoism teaches one to act by following the natural movement of things. It is in harmony with all things and opposes nothing. It takes what is good from Confucianism and Mohism, and retains the essentials of Legalism and the School of Names.
Sima Tan served as Grand Historian during the Jiangyuan era. He studied yin-yang under Tang Du, the Yi Jing under Yang He, and Taoism under Huang Shengong.
Key Places
Capital of the Western Han Empire, where Sima Tan served as Grand Astrologer for several decades. The imperial archives, astronomical observatory, and the court of Emperor Wu were all located there.
Sacred mountain where Emperor Wu held the Feng Shan ceremonies in 110 BCE. Sima Tan, too ill to attend, died of grief shortly afterward, according to the tradition recorded by his son.
Region along the Yellow River where the Sima family originated. Sima Tan likely spent his childhood there before moving to the capital to pursue his studies and his career at the imperial court.
The secret library of the Han court, where Sima Tan had access to thousands of historical documents, official annals, and ancient texts. It was here that he gathered the monumental sources that would form the foundation of the *Shiji*.
Typical Objects
The universal writing medium in China before the spread of paper, bamboo tablets bound with cords were used to record official archives. Sima Tan consulted and drafted his historical notes on these tablets, which his son Sima Qian describes as forming a vast collection in the imperial archives.
A fundamental astronomical instrument consisting of a vertical rod whose shadow is measured to determine the solstices and the height of the sun. As Grand Astrologer, Sima Tan used the gnomon for the official calendrical observations essential to the ritual life of the empire.
An instrument composed of rings representing the great celestial circles, used to measure the positions of celestial bodies. This sophisticated tool was at the heart of Sima Tan's astronomical observation work at the Han court, where reading the sky was as much a political function as a scientific one.
Yarrow stalks were used in divinatory consultations of the Yi Jing, which Sima Tan had studied under the master Yang He. This practice was inseparable from the role of court astrologer, charged with interpreting celestial signs to advise the emperor.
These bronze tripod cauldrons, symbols of imperial power and of exchange with the celestial world, stood at the center of the ceremonies that Sima Tan oversaw. The discovery in 113 BC of an ancient ding was an event that Sima Tan officially interpreted as a favorable omen.
The brush dipped in black ink was the indispensable tool of every Han scholar and historian. Sima Tan drafted his philosophical analyses and historical notes with these instruments, passing on his manuscripts and his method to his son Sima Qian.
School Curriculum
Vocabulary & Tags
Key Vocabulary
Daily Life
Morning
Sima Tan rose before dawn to observe the stars from the observation platform of the imperial court. He recorded on bamboo tablets the positions of the stars, the color of the sky, and any notable celestial phenomenon — shooting stars, lunar halos, planetary conjunctions — that might hold political or ritual significance for the empire.
Afternoon
The afternoon was devoted to consulting the imperial archives and to writing. Surrounded by silk scrolls and bundles of bamboo tablets covered in dynastic annals, Sima Tan combed through historical sources for his Memoirs project. He also occasionally received scholars or travelers who brought back information about the empire's distant regions.
Evening
In the evening, Sima Tan took part in the court's ritual ceremonies — offerings to the ancestors, libations, oracle readings — where his role as official astrologer was central. Back in his quarters, he would discuss philosophy with his son Sima Qian or compose his analyses of the schools of thought by the light of a bronze oil lamp.
Food
Like all high-ranking officials at the Han court, Sima Tan ate millet and rice, accompanied by fermented vegetables, dried fish, and — at official banquets — pork or mutton. Millet wine (jiu) was served during the ritual ceremonies he attended as an officer of the celestial cult.
Clothing
Sima Tan wore silk robes in colors coded according to his rank as an imperial official: a laced leather belt, an official cap (guan) of stiffened fabric held in place by jade or bronze pins. During major astronomical ceremonies, he donned ceremonial garments embroidered with celestial motifs befitting his title of Grand Astrologer.
Housing
Sima Tan resided in the imperial officials' quarters of Chang'an, a large residence of several inner courtyards with wooden buildings set on rammed-earth foundations and gray-tiled roofs. One room was fitted out as a workspace for bamboo tablets; another served as the space for the family ancestral ceremonies essential to any man of letters.
Historical Timeline
Period Vocabulary
Liens externes & ressources
Références
Œuvres
Shiji (Mémoires historiques) — conception et partie initiale
vers 120-110 av. J.-C.
Lun liu jia zhi yao zhi (Essai sur les points essentiels des six écoles de pensée)
vers 120 av. J.-C.
Observations astronomiques et travaux calendaires
130-110 av. J.-C.
