In 249, during the reign of Cao Rui's successor, Cao Fang, the regent Sima Yi seized state power from his co-regent, Cao Shuang, in a coup. This event marked the collapse of imperial authority in Wei, as Cao Fang's role had been reduced to that of a puppet ruler while Sima Yi wielded state power firmly in his hands. Wang Ling, a Wei general, tried to rebel against Sima Yi, but was swiftly dealt with, and took his own life. Sima Yi died on 7 September 251, passing on his authority to his eldest son, Sima Shi, who continued ruling as regent.
Sima Shi deposed Cao Fang in 254, on grounds of planning to stage a rebellion, and replaced him with Cao Mao. In response, Guanqiu Jian and Wen Qin staged a rebellion, but were crushed by Sima Shi in an event that nevertheless took a heavy toll on Sima Shi's health, having undergone eye surgery prior to the insurrection, causing him to die on 23 March 255, but not before handing his power and regency over to his younger brother, Sima Zhao.
In 258, Sima Zhao quelled Zhuge Dan's rebellion, marking an end to what are known as the Three Rebellions in Shouchun. In 260, Cao Mao attempted to seize back state power from Sima Zhao in a coup, but was killed by Cheng Ji, a military officer who was serving under Jia Chong, a subordinate to the Simas. After Cao Mao's death, Cao Huan was enthroned as the fifth ruler of Wei. However, Cao Huan was also a mere figurehead under Sima Zhao's control, much like his predecessor. In 263, Wei armies led by Zhong Hui and Deng Ai conquered Shu. Afterwards, Zhong Hui and former Shu general Jiang Wei grouped and plotted together in order to oust Sima Zhao from power, however, various Wei officials turned against them when it was found out that Jiang Wei had urged Zhong Hui to get rid of these officials before the planned coup. Sima Zhao himself received and finally accepted the nine bestowments and the title Duke of Jin in 263, and was further bestowed with the title King of Jin by Cao Huan in 264, but he died on 6 September 265, leaving the final step of usurpation up to his eldest son, Sima Yan.