Simplify the following text for a Grade 10 native English-speaking person.
Original: Mata Hari was the stage name of Margaretha Geertruida `` Grietje '' Zelle MacLeod ( 7 August 1876 , Leeuwarden â `` 15 October 1917 , Vincennes ) , a Dutch exotic dancer , courtesan , and accused spy who , although possibly innocent , was executed by firing squad in France for espionage for Germany during World War I.
Simplified: Mata Hari was the stage name of Margaretha Geertruida ( Grietje ) Zelle ( 7 August , 1876 , Leeuwarden , The Netherlands -- 15 October , 1917 , Vincennes , France ) . She was a Dutch-Frisian exotic dancer .