Simplify the following text for a Grade 8 native English-speaking person.
Original: Jacqueline Lee Bouvier Kennedy Onassis ( July 28 , 1929 â `` May 19 , 1994 ) was the wife of the 35th President of the United States , John F. Kennedy , and served as First Lady of the United States during his presidency from 1961 until his assassination in 1963 .
Simplified: Jacqueline Lee Bouvier Kennedy Onassis ( July 28 , 1929 - May 19 , 1994 ) , was the wife of President John F. Kennedy and First Lady of the United States from 1961 until his assassination in 1963 .