courtesy name
A courtesy name (), also known as a style name, is a name bestowed upon one at adulthood in addition to one's given name. This practice is a tradition in the East Asian cultural sphere, including China, Japan, Korea, and Vietnam.Ulrich Theobald ...
Dayou, was an imperial prince of the
Western Jin dynasty
Western may refer to:
Places
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*Western, New York, a town in the US
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*Western Junction, Tasmania, a locality in Australia
*Western world, countries that id ...
of China. He was the second son of Sima Zhao, a regent of the
Three Kingdoms
The Three Kingdoms () from 220 to 280 AD was the tripartite division of China among the dynastic states of Cao Wei, Shu Han, and Eastern Wu. The Three Kingdoms period was preceded by the Han dynasty#Eastern Han, Eastern Han dynasty and wa ...
period, and Zhao's wife
Wang Yuanji
Wang Yuanji (217 – 20 April 268) was a Chinese noble lady, aristocrat and later empress dowager of Jin dynasty, who lived during the Three Kingdoms period. She was the wife of Sima Zhao, a regent of the state of Cao Wei during the Three King ...
.
Sima You became the heir to his uncle,
Sima Shi
Sima Shi () (208 – 23 March 255), courtesy name Ziyuan, was a military general and regent of Cao Wei during the Three Kingdoms period of China. In 249, he assisted his father Sima Yi in overthrowing the emperor Cao Fang's regent Cao Shuang, al ...
, who eventually died without any sons. It is known that Sima You was a person of mild-mannered character, who was expected to become King of Jin, but ended up being passed over due to his young age. The heir that was eventually chosen was Sima Zhao's first son, Sima Yan (Emperor Wu), who usurped the Cao Wei throne and established the Jin dynasty with himself as the new emperor in February 266. Sima You was made Prince of Qi on 9 February 266.''dingmao'' day of the 12th month of the 1st year of the ''Taishi'' era, per Sima Yan's biography ''in Book of Jin''.
When Emperor Wu appointed his
developmentally disabled
Developmental disability is a diverse group of chronic conditions, comprising mental or physical impairments that arise before adulthood. Developmental disabilities cause individuals living with them many difficulties in certain areas of life, espe ...
son heir apparent, he was concerned that his subjects viewed Sima You too favourably. In order to strengthen his son's position, he ordered Sima You away from
Luoyang
Luoyang is a city located in the confluence area of Luo River (Henan), Luo River and Yellow River in the west of Henan province. Governed as a prefecture-level city, it borders the provincial capital of Zhengzhou to the east, Pingdingshan to the ...
in 282 to his fiefdom of Qi, despite protestations from their sisters, Princess Jingzhao and Princess Changshan. Sima You fell ill from the stress and died soon after at the age of 36 (by
East Asian age reckoning
Countries in the East Asian cultural sphere (China, Korea, Japan, Vietnam, and their diasporas) have traditionally used specific methods of reckoning a person's numerical age based not on their birthday but the calendar year, and what age one is ...
).
Sima You's son,
Sima Jiong
Sima Jiong (司馬冏) (before 283 - 27 Jan 303According to the ''Book of Jin'', Sima Jiong was defeated on the ''wuchen'' day in the 12th month of the year after the 1st year of the ''Yongning'' era of Emperor Hui's reign. This corresponds to 27 ...
, was one of the eight princes involved in the
War of the Eight Princes
The War of the Eight Princes, Rebellion of the Eight Kings, or Rebellion of the Eight Princes () was a series of civil wars among kings/princes (Chinese: ''wáng'' 王) of the Chinese Jin dynasty from 291 to 306 AD. The key point of contention in ...
during the reign of Emperor Hui, the second emperor of the Jin dynasty.
Records of the Three Kingdoms
The ''Records or History of the Three Kingdoms'', also known by its Chinese name as the Sanguo Zhi, is a Chinese historical text which covers the history of the late Eastern Han dynasty (c. 184–220 AD) and the Three Kingdoms period (220– ...
Book of Jin
The ''Book of Jin'' is an official Chinese historical text covering the history of the Jin dynasty from 266 to 420. It was compiled in 648 by a number of officials commissioned by the imperial court of the Tang dynasty, with chancellor Fang ...
Zizhi Tongjian
''Zizhi Tongjian'' () is a pioneering reference work in Chinese historiography, published in 1084 AD during the Northern Song dynasty in the form of a chronicle recording Chinese history from 403 BC to 959 AD, covering 16 dynast ...