proconsul (n.)

late 14c., "governor or military commander of an ancient Roman province," from Latin proconsul "governor of a province; military commander," from phrase pro consule "(acting) in place of a consul," from pro "in place of" (see pro-) + ablative of consul. In modern use usually rhetorical, but it was a title of certain commissioners in the French Revolution, was used in English for "deputy consul," and was used again of U.S. administrators in Iraq during the occupation. Related: Proconsular.