[Why] After the First Opium War, Britain and France were dissatisfied with the limited interests brought by the Treaty of Nanking and used the Arrow Incident and the Father Auguste Chapdelaine Affair to provoke a new round of invasion of China. The Xianfeng court faced joint Western attack with no way out. [What] The Anglo-French allied forces successively took Guangzhou, Tianjin, and Beijing, with Emperor Xianfeng fleeing in panic to Rehe Chengde. The allied forces unleashed soldiers to burn the Old Summer Palace, and the Qing court was forced to sign the Treaty of Tianjin and the Convention of Beijing, ceding land, paying indemnity, and opening more treaty ports. [Who] Emperor Xianfeng Yizhu was a tragic ruler with no countermeasure facing dimensionality-reduction strike. Prince Gong Yixin negotiated in the capital to save the perilous situation, while Anglo-French commander Elgin was the criminal mastermind who burned the Garden of Ten Thousand Gardens. [How] The burning of the Old Summer Palace became modern China's most painful memory of national shame, with foreign powers' influence penetrating deep into the heartland of North China. It pushed China further into the semi-colonial abyss and directly birthed the painful awakening of the Self-Strengthening Movement.
Why
The historic event of Anglo-French Expedition (Second Opium War) represents a key developmental peak of the Huaxia dynastic system. The burning of the Old Summer Palace and the deepening of semi-colonial subjugation. By establishing this moral or administrative benchmark, it continues to shape the structural and philosophical fabric of ancient Chinese statecraft.