Question

Why was the Cleveland Massacre significant in the formation of Standard Oil?

Answer 1

Standard Oil became a monopoly in the Cleveland oil market after the Massacre.

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Answer 2

It was actually Standard Oil that was significant in the formation of the Cleveland Massacre in the late 1870s. John D. Rockefeller's company called Standard Oil held a monopoly on the oil traffic in and out of Cleveland until the Supreme Court ruled it had to be split up in 1911.