A mandated country — more often a mandated territory — has been placed under another country’s control by an official international decision, not by a normal vote of the people who live there. This is mainly a history word. After the First World War, the League of Nations gave some lands of the old empires to other countries to run; those lands were mandated territories, and the power in charge held a mandate. The idea on paper was care and guidance; in practice it often looked a lot like taking the place. You will meet this in textbooks about the early twentieth century, not in everyday talk about today’s countries.