Simplify the following text for a Grade 11 native English-speaking person.
Original: Petra Karin Kelly ( 29 November 1947 -- presumably 1 October 1992 ) , a politician , was instrumental in founding the German Green Party , the first Green party to rise to prominence worldwide .
Simplified: Petra Karin Kelly ( November 23 , 1947 â `` October 1 , 1992 ) was a German politician , peace activist and one of the founders of the Green Party of Germany .