The African adventurer in question is Henry Morton Stanley, a Welsh-American journalist and explorer who is most famous for his exploration of Africa and his search for the missionary and explorer David Livingstone. He is also known for his work in establishing the Congo Free State, which was later annexed by Belgium. Stanley's expeditions were funded by the New York Herald newspaper, and he is remembered for his famous greeting to Livingstone: 'Dr. Livingstone, I presume?'