Simplify the following text for a Grade 4 native English-speaking person.
Original: Vasco da Gama , 1st Count of Vidigueira ( c. 1460 or 1469 -- 24 December 1524 ) was a Portuguese explorer , one of the most successful in the Age of Discovery and the commander of the first ships to sail directly from Europe to India .
Simplified: Vasco da Gama ( 1460 or 1469 ? - December 24 , 1524 ) was a Portuguese sailor .