Sima Zhou was born to Sima Yi and his concubine Lady Fu. He had three full brothers: Sima Liang, Sima Jing and Sima Jun. He started his career as a military officer in the Cao Wei state during the Three Kingdoms period. As a youth, he already had a reputation for his talent and also because of his family background; the Sima family had been the de facto rulers of Wei since 249. Sima Zhou was first appointed as Ningshuo General and put in charge of the security of the Wei nobles living in Ye city. Sometime during the Zhengshi era of Cao Fang's reign, he was enfeoffed as the Marquis of Nan'an Village. Later, he was promoted to a Regular Mounted Attendant and elevated from a village marquis to a district marquis under the title "Marquis of Dongwu District". In 260, the Wei emperor Cao Mao attempted to seize back power from the Sima family by staging a coup d'état against the regentSima Zhao. Sima Zhou, then holding the position of a Colonel of the Garrison Cavalry, led his troops to stop Cao Mao. However, his men dispersed in fear when Cao Mao shouted at them. Cao Mao eventually met his end at the hands of Cheng Ji, a subordinate of Sima Zhao's adviser Jia Chong. In 263, during the reign of Cao Huan, Sima Zhou was appointed as General of the Right and Inspector of Yan Province. A year later, after Sima Zhao restored the five-rank nobility system, which had previously been abolished, Sima Zhou was enfeoffed as the Count of Nanpi. He was also reassigned to be General Who Attacks Barbarians and granted imperial authority.
Life under the Jin dynasty
In 265, following Sima Zhao's death, his son Sima Yan usurped the throne from Cao Huan and established the Jin dynasty to replace the Cao Wei state, with himself as the new emperor. After his coronation, Emperor Wu enfeoffed his uncle Sima Zhou as the Prince of Dongguan with a princedom comprising 10,600 taxable households. He also granted permission to all the princes to appoint the county prefects/chiefs in the counties in their princedoms. Sima Zhou tried to ask Emperor Wu to remove this privilege but the emperor refused. In 268, Emperor Wu appointed Sima Zhou as Right Supervisor of the Masters of Writing and General Who Pacifies the Army. In the following year, he reassigned Sima Zhou to be Senior General Who Guards the East and granted him imperial authority to replace Wei Guan in supervising military affairs in Xu Province. During his tenure, Sima Zhou instilled good discipline among the troops and earned much respect from them. The militaryleaders in the Jin dynasty's rival state, Eastern Wu, were very wary of him. In 277, Emperor Wu heeded a suggestion by the minister Yang Yao and started reshuffling the various princes and their princedoms. As Sima Zhou was in Xu Province at the time, Emperor Wu enfeoffed him as the Prince of Langya while at the same time allowing him to retain his original princedom in Dongguan; Sima Zhou's princedom thus comprised both the commanderies of Dongguan and Langya. In 279, Sima Zhou participated in the Jin dynasty's campaign against Eastern Wu and led thousands of troops to attack the Wu position at Tuzhong. In 280, Sun Hao, the last Wu emperor, surrendered to the Jin dynasty. China was thus reunified under the Jin dynasty's rule. As a reward for Sima Zhou's contributions during the campaign, Emperor Wu enfeoffed two of Sima Zhou's sons as village marquises, each with a marquisate comprising 3,000 taxable households, in addition to granting him 6,000 rolls of silk. Some months later, Sima Zhou was reassigned to supervise military affairs in Qing Province and was given an additional appointment as a Palace Attendant. He was subsequently promoted to General-in-Chief and allowed to set up his own administrative office. When Sima Zhou became critically ill in 283, Emperor Wu bestowed several gifts on his family and even sent officials to visit him and enquire about his condition. Sima Zhou eventually died that year at the age of 57. Emperor Wu honoured him with the posthumous title "Prince Wu". Before his death, Sima Zhou had requested to be buried beside his mother Lady Fu after his death and for his princedom to be divided among his four sons: Sima Jin, Sima Dan, Sima Yao and Sima Cui. Emperor Wu approved his request. Among Sima Zhou's four sons, the eldest, Sima Jin, inherited his father's peerage as the Prince of Langya.
