The Opium War ended with a decisive British victory, forcing China to accept a punitive settlement that reshaped Sino-foreign relations. Britain’s naval power, modern steamships, and coastal artillery helped dominate sea lanes and compel Beijing to negotiate after opium suppression efforts and smuggling pressures failed. The resulting Treaty of Nanking (1842) became the first of the so‑called unequal treaties. China agreed to pay a large indemnity to Britain, cede Hong Kong Island in perpetuity,