After Muhammad Ali died Friday at the age of 74, many of the laudatory retrospectives on his life talked about Ali’s refusal to be drafted in the Vietnam War because of his Muslim beliefs. He took this stance at the prime of his boxing career, and his career never recovered from his forced four-year sabbatical from the sport.

Knowing what we do know about the Islamic State group, Al-Qaida, the Sunnis and the Shiites and the state of war the Middle East has been in — on and off — since 9/11, the idea that someone would refuse to fight because he’s a Muslim is so 20th century. And, if there’s any religion that’s been involved in warfare during this present century, it’s Islam. Was Ali, then, the earliest ambassador of Islam as the "religion of peace?"

Let's review: When Ali refused being inducted into the U.S. Army on April 28, 1967, conscientious objection to Vietnam was in its infancy, and his decision was criticized by even baseball great Jackie Robinson as hurting the morale of black soldiers fighting in Vietnam. 

I've read lots of recitations about Ali’s refusal to fight. But other than saying the boxer was refusing on the grounds of his religious beliefs, I've not seen any explanation of which beliefs those were. The Atlantic comes closest to bringing up the question but does not answer it:

In April 1967, Ali refused to be drafted to fight in the Vietnam War and was charged with draft evasion, resulting in a five-year prison sentence—he remained free pending appeal—and a large fine. The World Boxing Association stripped him of his heavyweight title, and Ali was effectively cast out of the boxing world in his physical prime.