Simplify the following text for a Grade 8 native English-speaking person.
Original: Richard Charles Albert Holbrooke ( April 24 , 1941 - December 13 , 2010 ) was an American diplomat , magazine editor , author , professor , Peace Corps official , and investment banker .
Simplified: Richard Charles Albert Holbrooke ( April 24 , 1941 - December 13 , 2010 ) was an US diplomat .