Event:
Robert de Geneve, "butcher of Cesena" crowned anti-pope Clemens VII
More Notable Events on September 20:
1990 Both Germanys ratify reunification
1985 Walt Disney World receives its 200-millionth guest
1967 British liner Queen Elizabeth II launched at Clydebank, Scotland
1945 German rocket engineers begin work in U.S.
1904 Orville and Wilbur Wright fly a circle in their Flyer II