Northwest Ordinance of 1787
The answer is first opium war
These ideas are most closely associated with no other than Karl Marx. He brought about this idea in his seminal work called the Communist Manifesto, where he talked about various things pertaining society and class struggles. Among them he also develope dthe notion of the dictatorship of the proletariat where the proletariat would have all the political power in a new type of society.
They were places where meeting of the big three allies were held
