poisoned. In his Zizhi Tongjian Kaoyi (资治通鉴考异), Sima Guang expressed his skepticism of this account. He argued that at this point, Sima Yi had just earned Cao Rui's trust, and showed no signs of disloyalty; his sons had no reasons to be disloyal as well. Thus, he didn't include this account in Zizhi Tongjian. Career up to 251 Incident at the Gaoping Tombs When Sima Yi started planning a coup d'état against Cao Shuang; according to the Jin Shu, Sima Yi confided only in Sima Shi, excluding even Shi's younger brother Sima Zhao from the discussion (although Sima Guang found this unlikely and, in his Zizhi Tongjian, opined that Sima Yi planned the coup with both Sima Shi and Sima Zhao). Sima Shi put together a group of 3,000 loyal men without knowledge by Cao Shuang or his associates, and when Sima Yi set to carry out his plans in 249, Sima Shi was able to quickly summon the men to carry out the coup. Once Sima Yi overthrew Cao Shuang and became the sole regent for the emperor, Cao Fang, he rewarded his son with the title Marquess of Changpingxiang, a large fief of 1,000 households, and shortly thereafter, the rank of General of the Guards (衛將軍). Sima Shi became his father's assistant, although there was no particular record of his accomplishments during these years. After Sima Yi died in 251, he took over his father's positions without significant opposition—after his father had, earlier that year, suppressed a failed rebellion by Wang Ling (王淩) and massacred the clans of Wang and his associates. As paramount authority During Cao Fang's reign Early regency Sima Shi would go on to rule the government effectively and impartially, ordering that all officials recommend talents to him, that they define the hierarchical ranks, take care of the impoverished and the orphaned, and deal with the delayed personnel affairs. Shortly after his father's death, the emperor appointed him to the position of General-in-Chief Who Pacifies the Army (撫軍大將軍). In late 251, Deng Ai, the Grand Administrator of Chengyang, submitted a memorial to the court in which he stated that the Xiongnu under Liu Bao were growing too powerful, and therefore proposed a method of giving the Xiongnu under Liu Bao titles and awards, so as to divide and weaken them, and to further settle them somewhere further away from the Chinese citizens and to reeducate