List of emperors of the Han dynasty
The Han dynasty was founded by the peasant rebel leader (Liu Bang), known posthumously as Emperor Gao ("r". 202 –195 BC) or Gaodi. The longest reigning emperor of the dynasty was Emperor Wu ("r". 141–87 BC), or Wudi, who reigned for 54 years. The dynasty was briefly interrupted by the Xin dynasty of the former regent Wang Mang, but he was overthrown in 23 AD and the Han dynasty was reestablished by Liu Xiu, known posthumously as Emperor Guangwu (r. 25–57 AD), or Guangwu Di. The last Han emperor, Emperor Xian ("r". 189–220 AD), was a puppet monarch of Chancellor Cao Cao (155–220 AD), who dominated the court and was made King of Wei. In 220 AD, Cao's son Pi usurped the throne as Emperor Wen of Wei ("r". 220–226 AD) and ended the Han dynasty.
Military history of the Three Kingdoms
On 11 December, 220, Cao Pi deposed the last Han emperor and proclaimed himself Emperor of Cao Wei. During his reign Cao Pi alienated his brothers Cao Zhang and Cao Zhi. Cao Pi deeply distrusted his close kin and reduced their powers out of suspicion of their loyalty. Cao Pi died in 226 and was succeeded by his son Cao Rui. Although Cao Rui was twenty years old, he was nonetheless appointed a regency council by his father prior to his death. By 236, three members of the regency council had died, leaving Sima Yi as the primary leader of Cao Wei. Shu Han continued to press the Wei borders and in 233, Zhuge Liang occupied Wudu Commandery. He was checked there by Sima Yi and died the following year. In 238 Sima Yi annexed the Gongsun state in the northwest. This was followed by a campaign into Goguryeo in 244 and 245. Cao Rui died in 239 and was succeeded by his adopted son Cao Fang, who fell under the regency of Cao Shuang and Sima Yi.