On 3 March 1857, amid escalating tensions over trade imbalances, diplomatic disputes, and the lingering effects of the First Opium War, Britain and France formally declared war on China, marking the intensification of the Second Opium War.
The conflict was triggered by the Arrow Incident, wherein British authorities accused Chinese officials of illegally seizing a British-registered ship, exacerbating existing hostilities.
Seizing the opportunity to assert greater control over Chinese trade and territory, France joined Britain in the military campaign, citing the execution of a French missionary as justification.
The war, driven by imperial ambitions and the opium trade, would ultimately force China into further concessions, deepening Western influence over its ports and policies.
