<Li> 1991--Retires from the Supreme Court . </Li> <Li> 1991--Received the Freedom medal </Li> <Li> 1992--Receives the U.S. Senator John Heinz Award for Greatest Public Service by an Elected or Appointed Official, an annual award by Jefferson Awards . </Li> <Li> 1992--Receives the Liberty Medal recognizing his long history of protecting individual rights under the Constitution . </Li>

Which african american leader became a justice in the supreme court