Muhammad Ali was honored with his own forever stamp by the United States Postal Service on Jan. 15. “I should be a postage stamp,” Ali famously once said, “because that’s the only way I’ll ever get licked.”

I attended the launch celebration in Louisville where Bob Costas served as the master of ceremonies. As I listened to each speaker share memories of The Greatest, I could not help but think about how grounded Ali was in his convictions.

I keep coming back to the part of Muhammad Ali’s story when he refused to be drafted for the Vietnam War. Many sought draft deferments due to marital, parental or student status as well as for medical reasons, and Ali wasn’t the only one who refused to serve due to religious and moral reasons. The term was “conscientious objector,” which according to Amnesty International was defined as being “people who are eligible for conscription but refuse to perform military service for reasons of conscience or profound conviction.”

Around 170,000 men received conscientious objector deferments during the Vietnam War, with 61,000 happening in 1971 following the Supreme Court decision that expanded the definition of what could be considered conscientious objection.

However, in 1967, the courts did not believe Ali was genuine in his objection. At his scheduled U.S. Armed Forces induction in Houston, they called his name three times, and three times Ali refused to step forward. He was warned of the consequences and given one more chance to comply. He did not.

Muhammad Ali knew from a very young age that he wanted to be a boxer. He worked tirelessly to make it a reality. He raced the school bus to school. He jumped rope between classes and after school, after his part-time job, he trained at the gym. He said, “Champions are made from something they have deep inside them — a desire, a dream, a vision.”

At the top of his game, the then-undefeated world heavyweight boxing champion was convicted of draft evasion on April 28, 1967. He was stripped of his heavyweight title, suspended from boxing, sentenced to five years in prison and fined $10,000.

“I ain’t got no quarrel with those Vietcong,” Ali said.

He stayed out of jail on bond for the three years it took to fight the ruling in court and win. And though many think of him fondly today, at the time he was a hated man.

Not only did Muhammad Ali stand up for his convictions, but he did so with swagger. He was loud and proud. He rejected Christianity as the religion of his oppressor. He changed his name from Cassius Clay to Muhammad Ali, denouncing his birth name as a “slave name,” for its ties to white ownership. He was a Black Muslim, which many felt had a militant connotation.

Muhammad Ali was radical. He was the “Louisville Lip,” audacious enough to think himself worthy and consider himself “The Greatest.” He took on the Vietnam War at a time when it still had public support. But while Ali was shunned from boxing and fighting in court, that tide began to turn. Over time, Muhammad Ali’s stance was validated.