Simplify the following text for a Grade 8 native English-speaking person.
Original: The Cathedral contains the world 's oldest working clock ( from AD 1386 ) and has the best surviving of the four original copies of Magna Carta ( all four original copies are in England ) .
Simplified: The Cathedral contains the world 's oldest working clock ( from AD 1386 ) . It also has one of the four surviving original copies of the Magna Carta ( all four original copies are in England ) .