Since the 19th century, many if not all presidents were assisted by a central figure or "gatekeeper", sometimes described as the <answer>President's Private Secretary</answer>, sometimes with no official title at all. Eisenhower formalized this role, introducing the office of White House Chief of Staff – an idea he borrowed from the United States Army. Every president after Lyndon Johnson has also appointed staff to this position. Initially, Gerald Ford and Jimmy Carter tried to operate without a chief of staff, but each eventually appointed one.
What 19th century informal political office did the modern role of White House Chief of Staff correspond to?
President's Private Secretary