Simplify the following text for a Grade 11 native English-speaking person.
Original: Samuel Pepys FRS , MP , JP , ( ; 23 February 1633 â `` 26 May 1703 ) was an English naval administrator and Member of Parliament , who is now most famous for the diary he kept for a decade while still a relatively young man .
Simplified: Samuel Pepys , ( 23 February 1633 â `` 26 May 1703 ) was an English administrator at the Admiralty and Member of Parliament , who is now most famous for his diary .