Final answer:
King Leopold II of Belgium controlled the Congo Free State, an area much larger than Belgium, recognized by the Berlin Conference.
Step-by-step explanation:
The European king who personally controlled an area in Africa seventy-five times the size of his own country was King Leopold II of Belgium. Under his rule, the Congo Free State was established as essentially his private enterprise, which he exploited for resources like ivory and rubber. Despite the pretense of humanitarian aims, Leopold's regime in the Congo was characterized by significant brutality and exploitation. This control was legitimized at the Berlin Conference, where other European powers recognized his claims over the territory.