Simplify the following text for a Grade 7 native English-speaking person.
Original: Arthur Tudor , Prince of Wales ( 19\/20 September 1486 -- 2 April 1502 ) was the first son of King Henry VII of England and Elizabeth of York , and therefore , heir to the throne of England .
Simplified: Arthur Tudor ( 19 or 20 September 1486 - 2 April 1502 ) was the oldest son of Henry VII and Elizabeth of York .