Cao Wei

Beginnings and founding

A bronze crossbow trigger mechanism, Wei dynasty, 242 AD

Towards the end of the Eastern Han dynasty, northern China came under the control of Cao Cao, the chancellor to the last Han ruler, Emperor Xian. In 213, Emperor Xian granted Cao Cao the title of "Duke of Wei" (魏公) and gave him ten cities as his dukedom. The area was named "Wei". At that time, the southern part of China was divided into two areas controlled by two other warlords, Liu Bei and Sun Quan. In 216, Emperor Xian promoted Cao Cao to the status of a vassal king — "King of Wei (魏王)" — and granted him more territories.

Cao Cao died on 15 March 220 and his vassal king title was inherited by his son Cao Pi. Later that year, on 11 December, Cao Pi forced Emperor Xian to abdicate in his favour and took over the throne, establishing the state of Wei. However, Liu Bei immediately contested Cao Pi's claim to the Han throne and declared himself "Emperor of Shu Han" a year later. Sun Quan was nominally a vassal king under Wei, but he declared independence in 222 and eventually proclaimed himself "Emperor of Wu" in 229.

Reigns of Cao Pi and Cao Rui

Cao Pi ruled for six years until his death in 226 and was succeeded by his son, Cao Rui, who ruled until his death in 239. Throughout the reigns of Cao Pi and Cao Rui, Wei had been fighting numerous wars with its two rival states — Shu and Wu.

Between 228 and 234, Zhuge Liang, the Shu chancellor and regent, led a series of five military campaigns to attack Wei's western borders (within present-day Gansu and Shaanxi), with the aim of conquering Chang'an, a strategic city which lay on the road to the Wei capital, Luoyang. The Shu invasions were repelled by the Wei armies led by the generals Cao Zhen, Sima Yi, Zhang He and others; Shu did not make any significant gains in the expeditions.

On its southern and eastern borders, Wei engaged Wu in a series of armed conflicts throughout the 220s and 230s, including the battles of Dongkou (222-223), Jiangling (223) and Shiting (228). However, most of the battles resulted in stalemate and neither side managed to significantly expand its territory.

Goguryeo–Wei Wars

Around that time, as the Korean kingdom Goguryeo consolidated its power, it proceeded to act to conquer the territories on the Korean peninsula which were under Chinese rule.^[5] Goguryeo initiated the Goguryeo–Wei Wars in 242, trying to cut off Chinese access to its territories in Korea by attempting to take a Chinese fort. However, Wei responded by invading and defeated Goguryeo. Hwando was destroyed in revenge by Wei forces in 244.^[5]

Fall of Wei

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 a puppet ruler while Sima Yi wielded state power firmly in his hands. Sima Yi died in 251 and passed on his authority to his eldest son, Sima Shi, who continued ruling as regent. Sima Shi deposed Cao Fang in 254 and replaced him with Cao Mao. After Sima Shi died in the following year, his younger brother, Sima Zhao, inherited his power and status as regent. In 260, Cao Mao attempted to seize back state power from Sima Zhao in a coup, but was killed by Sima's subordinate, Cheng Ji (成濟).

After Cao Mao's death, Cao Huan was enthroned as the fifth ruler of Wei. However, Cao Huan was also a figurehead under Sima Zhao's control much like his predecessor. In 263, Wei armies led by Zhong Hui and Deng Ai conquered Shu. On 4 February 266,^{[lower-alpha 1]} Sima Zhao's son, Sima Yan, forced Cao Huan to abdicate in his favour, replacing Wei with the Jin dynasty on 8 February.^{[lower-alpha 3]}