Simplify the following text for a Grade 13 native English-speaking person.
Original: During the Civil War , postal services in the Confederacy were provided by the Confederate States of America Post Office Department , headed by Postmaster General John Henninger Reagan .
Simplified: During the Civil War ( 1861 â `` 65 ) , postal services in the Confederacy were provided by the CSA Post Office Department , headed by Postmaster General John Henninger Reagan .