Liu Zhang vs Zhang Qian

Liu Zhang invited Liu Bei into Yi Province to help defend against the threat from Zhang Lu in Hanzhong. This decision allowed Liu Bei to establish a foothold in the province, ultimately leading to Liu Zhang's downfall.

Liu Zhang, Governor of Yi Province, surrendered to Liu Bei after a prolonged siege of Chengdu. Liu Bei had been invited to help defend against Zhang Lu but instead turned on Liu Zhang, taking control of the province.

Emperor Wu of Han dispatched Zhang Qian as an envoy to seek an alliance with the Yuezhi against the Xiongnu. Zhang Qian was captured by the Xiongnu and held for ten years, but eventually escaped and continued his journey.

After escaping Xiongnu captivity, Zhang Qian traveled through Ferghana and Sogdiana to reach the Yuezhi in Bactria. The Yuezhi declined an alliance against the Xiongnu, but Zhang Qian gathered detailed intelligence on Central Asian states.

Zhang Qian returned to the Han capital after 13 years, bringing detailed accounts of the Western Regions, including the kingdoms of Dayuan, Kangju, and Daxia. His report provided the first reliable Chinese knowledge of Central Asia and spurred Han expansion.

Emperor Wu sent Zhang Qian on a second mission to the Wusun in the Ili Valley to secure an alliance against the Xiongnu. Zhang Qian established diplomatic relations and opened the Silk Road trade routes between China and Central Asia.