(Above: Frank Langella as Chief Justice Warren Burger and Christopher Plummer as John Marshall Harlan in Muhammad Ali's Greatest Fight.)

Cassius Clay is regarded, to this day, as one of the greatest heavyweight boxers in the sport's history. But Muhammad Ali, as he renamed himself and is better known, was a force to be reckoned with outside of the ropes as well. Muhammad Ali's Greatest Fight, coming this October from HBO Films, looks at Ali's refusal to fight in the Vietnam War and the historic Supreme Court battle that followed.

Watch the trailer below and set your DVR for October 5.

Photo Credit: Jojo Whilden