[Why] The High Tang's expansion in the Western Regions reached the Transoxiana region of Central Asia, producing direct collision with the newly risen Arab Abbasid Caliphate. The Qarluq and other Central Asian tribes hedged on the fence between the two empires. [What] The Anxi Deputy Military Commissioner Gao Xianzhi led twenty thousand Tang troops on a far expedition into Central Asia and at the Talas River fought the Arab general Ziyad's hundred-thousand-strong allied force. The Qarluq suddenly switched sides, and the Tang army was crushed with thousands captured. [Who] Gao Xianzhi was an outstanding Goguryeo-descended Tang general who had once shaken the Pamirs. The Arab general Ziyad was the core military commander of the Abbasid eastward expansion, and Tang craftsmen among the captives rewrote world technology history. [How] This battle marked the ultimate peak and the turning back of Tang expansion in Central Asia. The captured Tang craftsmen carried papermaking to the Arab world, opening the epic of global civilizational transmission of East-to-West papermaking transfer.
Why
The historic event of Battle of Talas represents a key developmental peak of the Huaxia dynastic system. The pivotal Tang-Arab collision and the launch of papermaking westward across the world. By establishing this moral or administrative benchmark, it continues to shape the structural and philosophical fabric of ancient Chinese statecraft.