Simplify the following text for a Grade 7 native English-speaking person.
Original: In 1993 , PLO chairman Yasser Arafat recognized the State of Israel in an official letter to its prime minister , Yitzhak Rabin .
Simplified: The leader of the PLO used to be Yasser Arafat . He signed a series of Peace Treaties called the Oslo Accords with Yitzhak Rabin who the Prime Minister of Israel at the time .