Source 1: The Opium Wars - Treaty of Tientsin (1858)
"The Emperor of China shall accept the establishment of British consuls in the treaty ports. In addition, foreign merchants and missionaries shall enjoy full protection, and the opium trade shall remain unrestricted under British control. The territories of Hong Kong and the ports of Canton, Fuzhou, Ningbo, and Shanghai shall be opened to foreign trade."
What was the primary impact of the Treaty of Tientsin on China's sovereignty?