Emperor Xian of Han
Cao Cao died on 15 March 220. His son and successor, Cao Pi, soon forced Emperor Xian to abdicate the throne in favour of himself, ending the Han dynasty. Cao Pi established a new state known as Cao Wei (sometimes known inaccurately as the Kingdom of Wei), and he granted Emperor Xian a noble title – Duke of Shanyang (山陽公). The former Emperor Xian died in 234 and was buried with honours befitting an emperor, using Han ceremonies, and the then emperor of Wei, Cao Rui, was one of the mourners. As Emperor Xian's crown prince was already dead, his grandson Liu Kang (劉康) inherited his dukedom, which lasted for 75 more years and two more dukes, Liu Jin (劉瑾) and Liu Qiu (劉秋), until the line was exterminated by invading Xiongnu tribes in about 309, during the Jin dynasty. This practice of an emperor conferring hereditary nobility on his predecessor, from whom he usurped the throne, was known as "er wang san ke" (二王三恪).
Emperor Hui of Han
Emperor Hui of Han (210 BC – 26 September 188 BC) was the second emperor of the Han Dynasty in China. He was the second son of the first Han emperor, Han Gaozu and Empress Dowager Lü. He is generally remembered as a weak character dominated by his mother, Empress Dowager Lü, personally kind and generous, but unable to escape the impact of her viciousness. He tried to protect Ruyi, Prince Yin of Zhao, his younger half-brother, from being murdered by Empress Dowager Lü, but failed. After that, he indulged himself in drinking and sex, and died at a relatively young age. Empress Dowager Lü installed two of his sons, Liu Gong and Liu Hong (known collectively as Emperors Shao of Han), the sons of the Emperor's concubine(s) after he died without a designated heir. Emperor Hui's wife was Empress Zhang Yan, a niece of his by his sister Princess Yuan of Lu; their marriage was the result of insistence by Empress Dowager Lü and was a childless one.