Simplify the following text for a Grade 12 native English-speaking person.
Original: John of Gaunt ( Ghent ) , 1st Duke of Lancaster ( second creation ) , KG ( 6 March 1340 -- 3 February 1399 ) was a member of the House of Plantagenet , the third surviving son of King Edward III of England and Philippa of Hainault .
Simplified: John of Gaunt , 1st Duke of Lancaster , 1st Duke of Aquitaine ( 6 March 1340 â `` 3 February 1399 ) was a member of the House of Plantagenet , the third surviving son of Edward III of England and Philippa of Hainault .