Leopold II tried to convince the Belgian government to embark on a colonization project of the Congo, but he could not produce a coalition, weary as the nation was with colonization. So, he established the territory as a “philanthropic” company under his personal control.
This decisions was approved by the other European colonial powers, which is as close as you can get to something like the UN Security Council at the time. They approved the plan on the expectation that Leopold would improve the lives of the natives. He felt no compunction about violating this expectation.
And remember, many colonial projects were envisioned as companies, not countries, though the difference is mostly metaphor. Leopold was the head of the company and effective sovereign of territory, just as others had owned companies responsible for earlier mercantilist expansions. He would become immensely wealthy in his role, as those who do not mind leaving a trail of corpses sometimes do.
It seems impossible under our modern understanding of nation states for someone to just claim such a swathe of land for themselves. But remember, such strong states did not exist in Africa at the time. European nations could easily set up shop with their superior might, and then cast themselves as “civilizing” the native people while supporting their political, military, and economic goals. And without an existing nation state to stand against Leopold’s ambitions, who would stop him?
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