Ali refuses induction and loses his prime
On April 28, 1967, in Houston, Muhammad Ali refused to step forward for induction into the U.S. Army, citing his ministry in the Nation of Islam. Boxing authorities stripped him of his heavyweight title and denied him licenses, and he was convicted of draft evasion and sentenced to five years in prison and a $10,000 fine. He lost about three and a half years of his athletic prime before the Supreme Court unanimously overturned the conviction in 1971, in Clay v. United States.