Leopold II of Belgium Ruled between 1865 and 1909 , his full name Leopold Louis Philippe Marie Victor , born on 9 April 1835 in Brussels , and died on 17 December 1909 in Leiken, Belgium .One of the most prominent perpetrators of massacres in modern history, when he was killed in the control of African regions more than 10 million people, Leopold II led the first European efforts to develop the Congo River Basin, creating conditions for the formation of the Free Congo State in 1885 , and annexed to Belgium in 1908 on behalf of the Belgian Congo (Today known as Congo Kinshasa.)