Simplify the following text for a Grade 9 native English-speaking person.
Original: Dirk Hartog ( baptized 30 October 1580 , Amsterdam-buried 11 October 1621 , Amsterdam ) was a 17th century Dutch sailor and explorer .
Simplified: Dirk Hartog ( 30 October 1580 , Amsterdam-buried 11 October 1621 , Amsterdam ) was a Dutch sailor and explorer .