Zack Clayton, Black Pioneer, first African-American to referee a world heavyweight title fight. In 1952 he refereed Ezzard Charles and Jersey Joe Walcott.
He also refereed "Rumble in the Jungle" which I found hard to forgive him for. Ali was like leech in that fight.
Clayton was a gifted athlete, playing baseball in the Negro leagues and also playing basketball for the Harlem Globetrotters.