Simplify the following text for a Grade 8 native English-speaking person.
Original: After Cromwell 's death , and his son Richard 's resignation as Lord Protector , Charles II was invited to return as monarch in 1660 with the Restoration .
Simplified: When Cromwell died , his son Richard was not strong enough to rule , and King Charles II , the son of Charles I , was invited to come to England and be king in 1660 .