1900

May

 * 17 - The Doctor is present at the Relief of Mafeking. ("The Daleks' Master Plan")


 * Unknown Date - The War Lords kidnap troops from the Boxer Rebellion in China for use in their War Games. ("The War Games")

February

 * 21 - Sydney Arnold, who played Perkins in "The Highlanders," is born in London.

May

 * 15 - American author L. Frank Baum's book, The Wonderful Wizard of Oz, is first published. Elements from the story and the 1939 musical film adaptation will be incorporated into several Doctor Who stories.