Simplify the following text for a Grade 3 native English-speaking person.
Original: Frank Heller was the pen name of the Swedish writer Gunnar Serner ( July 20 , 1886 - October 14 , 1947 ) .
Simplified: His real name was Gunnar Serner . He lived from July 20 , 1886 - October 14 , 1947 .