Originally known as Cassius Clay, Ali changed his name after joining the Nation of Islam in 1964, subsequently converting to Sunni Islam in 1975 and more recently to Sufism. In 1967, Ali refused to be inducted into the U.S. military, based on his religious beliefs and opposition to the Vietnam War.
He was arrested and found guilty on draft evasion charges, stripped of
his boxing title, and his boxing license was suspended. He was not
imprisoned, but did not fight again for nearly four years while his
appeal worked its way up to the U.S. Supreme Court, where it was successful.