Ruzi Ying
Ruzi Ying (; 5 – 25), also known as Emperor Ruzi of Han and the personal name of Liu Ying (劉嬰), was the last emperor of the Chinese Western Han Dynasty from 6 CE to 9 CE. After Emperor Ai of Han and Emperor Ping died without heirs, Wang Mang chose the youngest of the available successors in order to maintain his power in the government. The child Ying was soon deposed by Wang Mang who declared the Xin Dynasty in place of the Han. During Xin Dynasty, Ying was under effective house arrest—so much so that as an adult, he did not even know the names of common animals. Before and after the Xin Dynasty was overthrown in 23 CE, many ambitious people claimed to be restoring the Han dynasty. In 25 CE, a rebellion against the temporary Gengshi Emperor used the former Emperor Ruzi as a focus, and when the rebellion was defeated, he was killed. He is often viewed as an innocent child who was the victim of tragic circumstances. (The expression "Emperor Ruzi" is a misnomer, as he never assumed the throne and was only named crown prince. Nevertheless, he is commonly referred to as such.)
Han dynasty
The Xiongnu, a nomadic steppe confederation, defeated the Han in 200 BC and forced the Han to submit as a "de facto" inferior and vassal partner, but continued their military raids on the Han borders. Emperor Wu launched several military campaigns against them. The ultimate Han victory in these wars eventually forced the Xiongnu to accept vassal status as Han tributaries. These campaigns expanded Han sovereignty into the Tarim Basin of Central Asia, divided the Xiongnu into two separate confederations, and helped establish the vast trade network known as the Silk Road, which reached as far as the Mediterranean world. The territories north of Han's borders were quickly overrun by the nomadic Xianbei confederation. Emperor Wu also launched successful military expeditions in the south, annexing Nanyue in 111 BC and Dian in 109 BC, and in the Korean Peninsula where the Xuantu and Lelang Commanderies were established in 108 BC. After 92 AD, the palace eunuchs increasingly involved themselves in court politics, engaging in violent power struggles between the various consort clans of the empresses and empresses dowager, causing the Han's ultimate downfall. Imperial authority was also seriously challenged by large Daoist religious societies which instigated the Yellow Turban Rebellion and the Five Pecks of Rice Rebellion. Following the death of Emperor Ling (r. 168–189 AD), the palace eunuchs suffered wholesale massacre by military officers, allowing members of the aristocracy and military governors to become warlords and divide the empire. When Cao Pi, King of Wei, usurped the throne from Emperor Xian, the Han dynasty ceased to exist.