Simplify the following text for a Grade 9 native English-speaking person.
Original: Eleanor `` Nell '' Gwyn ( or Gwynn or Gwynne ) ( 1650 - 14 November 1687 ) , was one of the earliest English actresses to receive prominent recognition , and a long-time mistress of King Charles II .
Simplified: Eleanor `` Nell '' Gwyn ( or Gwynn or Gwynne ) ( 2 February 1650 â `` 14 November 1687 ) was a long-time mistress of King Charles II of England .