Simplify the following text for a Grade 9 native English-speaking person.
Original: Preston M. `` Pete '' Geren , III ( born January 29 , 1952 in Fort Worth , Texas ) served as the 20th United States Secretary of the Army from July 16 , 2007 to September 16 , 2009 .
Simplified: Preston M. Geren , III ( born January 29 , 1952 in Fort Worth , Texas ) was the 20th United States Secretary of the Army from 16 July 2007 to 16 September 2009 .