In 1966, Ali refused to fight the Vietnam war -- it was compulsory then for most young American men, especially blacks, to join the US army -- saying, 'I got nothing against no Viet Cong. No Vietnamese ever called me a nigger.'
As a result, he was stripped of his boxing license and his heavyweight title. He was inactive from March 22, 1967 to October 1970, which many feel would have been his best years in the ring.
He appealed against his ban and the US Supreme Court unanimously voted in his favour.
During the trial, he insisted that the lawyers address him as Ali and not by his Christian name, Clay. 'It was a slave name given by a white man,' he declared.