they got it from India then manufactured the opium
If you're referrring to the opium wars between China and Britain, the British bought opium from growers in India (which was under British control at the time).
The tea and Opium trade
There were 2 Opium Wars, the First Opium War was from 1839-1842 the Second Opium War was from 1856-1860
First Opium War
One way in which the Sepoy Rebellion in India and the Boxer Rebellion China similar is that they attempted to
Britain and China
Britain
China.
The tea and Opium trade
Two.
The opium wars were never signed. Wars are declared or undeclared, not signed.