Mata Hari (1876-1917) was the stage-name for Dutch-born Margaretha Geertruida (Grietje) Zelle. She began her career as an exotic dancer, taking the name Mata Hari (meaning “sun” or “Eye of the Dawn”) in Paris. She posed herself as a princess from Java.

She mixed with the upper class and became a courtesan to many important high-ranking military men and politicians. This put her in a very good position to gather information. During World War 1, the Netherlands remained a neutral nation, enabling Mata Hari, a Dutch national, to cross national borders freely. At one point, she was interviewed by British Intelligence and she admitted to being a spy for the French. The French later denied this. It is still unknown whether this was true.

In January 1917, the German Military Attaché in Madrid sent an encoded radio signal to Berlin, stating that they were receiving excellent information from a German spy code-named H-21. French intelligence agencies intercepted the messages and were able to identify H-21 as Mata Hari. On February 13, 1917, Mata Hari was arrested in her Paris hotel room. She was subsequently tried for espionage and found guilty. She was executed by a firing squad on September 15, 1917 at the age of 41.