Sima Gan
Sima Gan, courtesy name Ziliang, was the youngest son of Sima Yi and his main wife Zhang Chunhua, and a younger brother of Sima Shi and Sima Zhao. Sima Yi, Sima Shi and Sima Zhao eventually became regents of the Cao Wei state during the Three Kingdoms era.
Life under Cao Wei
Sima Gan was born in 232 during the reign of Cao Rui, as the youngest son of Sima Yi and his wife Zhang Chunhua. Like his brothers, Sima Gan was given various posts and titles during the Cao Wei era; unlike them, Gan's posts and titles were largely minor or ceremonial.The first recorded historical event Sima Gan was involved in was the attempted coup by Cao Mao, by then a puppet under Sima Zhao's control. In June 260, Cao Mao launched a coup in an attempt to seize back power from Sima Zhao. Man Changwu was in charge of guarding one of the palace gates. Sima Gan led his men to the palace to assist Sima Zhao, but Man Changwu refused to let him pass and told him to enter through another gate instead. Later, when Sima Zhao asked Sima Gan why he was late, Sima Gan told him what happened.
Sima Zhao was made Prince of Jin on 2 May 264. With this elevation, when Sima Zhao established the Five Feudal Ranks of Zhou, Sima Gan was made Count of Dingtao.
During the Jin era
Sima Zhao died in September 265, and was succeeded as regent of Cao Wei by his son Sima Yan. In February 266, Sima Yan accepted Cao Huan's abdication and founded the Jin dynasty. Sima Gan was then made Prince of Pingyuan, with a fiefdom of 11,300 households. Although his fiefdom was large, he did not take an active role in administration; instead, he appointed officials based on their abilities and the positions which needed to be filled. He also allowed his income to accumulate and rot.Sima Yan died in May 290, and his son Sima Zhong ascended the throne. During audiences with the emperor, as the emperor's great-uncle, Sima Gan was allowed to wear his shoes and carry his sword, as well as walk at a normal pace.
The Book of Jin recorded several anecdotes between Sima Gan and his grandnephew Sima Jiong. During the War of the Eight Princes, after Sima Jiong defeated Sima Lun, while other clansmen of the Sima family and court officials sent oxen and wine as gifts to Sima Jiong, Sima Gan offered him 100 cash. At their meeting, Sima Gan said, "The Prince of Zhao caused a rebellion and you managed to put it down; that is your credit. Now, I'm congratulating you using these 100 cash. Even so, it is very difficult to remain at a high position; you must be careful and cautious." After becoming regent, Sima Jiong once received a visit from his great-uncle. While Sima Jiong stepped out of the house and received Sima Gan with courtesy, upon entering the house, Sima Gan sat down on Jiong's bed and did not allow Jiong to be seated. Gan then said, "You must not emulate the son of that Bai woman." After Sima Jiong was killed in January 303, Sima Gan cried bitterly and told those around him, "The Sima clan is waning; only this child is the most capable. Now that he has died, the Sima clan is in peril!"
After Sima Yue became Emperor Hui's last regent in 306, he decided to pay Sima Gan a visit at Gan's residence in Luoyang. Gan declined to meet him; after a lengthy wait, Gan despatched a servant to see Yue off. At the same time, Gan left the door ajar, allowing him to observe the scene from behind the door. At the time, people could not understand his actions; they thought that Gan was ill, or that he had turned reclusive.