March 20, 1413 - Death of Henry IV in the Jerusalem Chamber at Westminster Abbey; buried at Canterbury Cathedral, Canterbury, Kent
My photo of Henry IV's tomb at Canterbury Cathedral, March 2008

March 20, 1469 - Birth of Cecily of York, daughter of Edward IV, at the Palace of Westminster
March 20, 1811 - Birth of Napoleon II (Francois-Charles-Joseph Bonaparte), son of Napoleon I and his second wife Marie-Louise of Austria, at the Tuileries Palace, Paris, France
March 20, 1816 Death of Maria I of Portugal in Rio de Janeiro, Brazil; buried first in the Ajuda Abbey in Rio de Janeiro, since 1821 in the Basílica da Estrela, Lisbon
March 20, 1926 Death of Lovisa of Sweden, wife of Frederik VIII of Denmark, at Amalienborg Palace, Copenhagen; buried at Roskilde Cathedral
March 20, 1934 Death of Emma of Waldeck and Pyrmont, wife of William III of the Netherlands, at the Palace Lange Voorhout, The Hague, Netherlands; buried at Nieuwe Kerk, Delft
March 20, 1974 - Kidnap attempt is made on Princess Anne in The Mall near Buckingham Palace
March 20, 1982 - Wedding of Prince Nikolaus of Liechtenstein and Princess Margaretha of Luxembourg at Notre Dame Cathedral in Luxembourg
March 20, 2004 - Death of Princess Juliana of the Netherlands, formerly Queen Juliana, at the Soestdijk Palace in Baarn, the Netherlands; buried at the Nieuwe Kerk in Delft