Historical clue formulations

• Who said "Without promotion, something terrible happens ... nothing!" — 2017-09-15
• Showman associated with the quote "There's a sucker born every minute" — 2011-11-07
• "The Humbugs of the World" author, 1865 — 2010-12-31
• Businessman/entertainer who was once mayor of Bridgeport, Conn. — 2009-08-07
• Lord of the rings? — 2005-08-19
• Exhibitor of Jumbo the elephant — 2005-01-09