Emperor Yang of Sui vs Wu Zetian

Emperor Yang ordered the construction of the Grand Canal, linking the Yellow River and Yangtze River basins. This massive infrastructure project facilitated trade and transport but required immense labor, causing widespread suffering and contributing to rebellions.

Emperor Yang launched a massive invasion of the Korean kingdom of Goguryeo with over 300,000 troops. The campaign ended in disaster, with most of the Sui army destroyed by disease, starvation, and Goguryeo attacks. This defeat severely weakened the Sui dynasty.

Emperor Yang launched a second invasion of Goguryeo. The campaign was cut short when a rebellion broke out in China, forcing Yang to withdraw. This further drained the dynasty's resources and morale.

Emperor Yang launched a third invasion of Goguryeo. Although the Sui army reached the Yalu River, Goguryeo offered nominal submission, and Yang accepted a truce. This campaign further exhausted the Sui treasury and military.

Emperor Yang was assassinated by his own guards in Jiangdu (modern Yangzhou) during a rebellion. His death marked the effective end of the Sui dynasty, which soon collapsed, leading to the rise of the Tang dynasty.

Wu Zetian was elevated from concubine to empress consort of Emperor Gaozong of Tang in 655. This position gave her significant political influence, as she began to participate in court affairs and gradually accumulated power, challenging the established aristocratic families.

After Emperor Gaozong's death in 683, Wu Zetian became regent for her son, Emperor Zhongzong. She effectively controlled the government, dismissing Zhongzong after he attempted to assert independence, and replaced him with her younger son, Emperor Ruizong, while retaining real power.

Wu Zetian proclaimed herself emperor, founding the Zhou dynasty and becoming the only female emperor in Chinese history. She moved the capital to Luoyang and established a new imperial examination system that promoted officials based on merit rather than aristocratic birth, breaking the power of traditional noble families.

Wu Zetian ordered military campaigns that reasserted Chinese control over the Western Regions, including the Tarim Basin and parts of modern Xinjiang. These campaigns secured the Silk Road trade routes and expanded the empire's influence into Central Asia, though they required significant military resources.

Wu Zetian elevated Buddhism to a state-supported religion, commissioning the construction of temples and statues, including the Longmen Grottoes' giant Vairocana Buddha. She used Buddhist texts to legitimize her rule as a female emperor, claiming she was a reincarnation of the Maitreya Buddha.

In 705, a coup led by court officials and generals forced Wu Zetian to abdicate in favor of her son, Emperor Zhongzong, restoring the Tang dynasty. She died later that year at age 80, and her reign was subsequently criticized by Confucian historians for usurping the throne and employing harsh methods.