Muhammad Ali – 'The Greatest' – died today in 2016. He suffered septic shock while hospitalised in Scottsdale, Arizona.

But he could have died 49 years earlier somewhere in Vietnam.

On the 28th April 1967, a 25-year-old Ali arrived at a US Army base in Houston, Texas. The then heavyweight champion of the world had been drafted to fight for America in its war against the Vietnamese people and this was his scheduled induction.

But when the recruiting sergeant called out "Muhammad Ali", he refused to step forward. He was asked two more times – two more refusals.

He was then promptly arrested for 'draft-dodging', his boxing license was revoked and his champion's belt was taken from him.

Muhammad Ali's words against the war 

Ali was publicly reviled by a country still enthusiastic for America's war of conquest in South-East Asia and he wouldn't be able to play the sport he loved for three years.

Sure, he could have followed the rules, done his training in Texas and shipped out to Vietnam as 'Private Ali' – a real American hero. There's a good chance he would have died ignominiously soon after - at Khe Sanh or Saigon (black soldiers suffered a disproportionate number of US casualties in Vietnam, after all).

But this didn't happen. Ali never put on the US army uniform.

This wasn't because he was a cowardly hypocrite like the young Donald Trump (who got no fewer than four deferrals of military service in the 1960s). Ali didn't 'dodge' the draft – he looked it right in the eyes and refused it.

The Kentucky-born prize fighter thought, along with the contemporary American Left, that the US presence in Vietnam was imperialist and so to serve there was a moral wrong.

Ali's inspiration for the anti-war movement 

Thank God for Ali's conscience, eh? His stand against the US government over Vietnam inspired others.Martin Luther King took up the anti-war movement soon after Ali refused the draft. When asked why, the Reverend answered: "Like Muhammad Ali puts it, we are all – black and brown and poor – victims of the same system of oppression."

From the late 1960s, domestic pressure against the Vietnam War grew and grew, while the military defiance faced in Vietnam held strong. By 1975, the US had effectively given up.

Muhammad Ali's refusal of the Draft played a role in making this happen.

What's more, it meant he was able to live a full life. Rather than being killed in 1968 or 1969 for something he didn't believe in, Ali lived 'til 2016 fighting for causes that he did.

A life of defiance 

As well as reclaiming his championship belt (twice), Ali maintained his tireless commitment to solidarity with the racially and economically oppressed – the same solidarity he took into that army base in 1967.

In 1974, he visited a Palestinian refugee camp in Lebanon where he declared his "support for the Palestinian struggle to liberate their homeland." Muhammad Ali remained a vocal advocate of Palestinian liberation for the rest of his life.

Four years later, he took part in 'The Longest Walk' – a protest march in the US supporting Native American rights.

In 1990, he visited Nelson Mandela in South Africa upon the anti-Apartheid leader's release from prison. Mandela – a boxer himself – remembered feeling "extremely apprehensive. I wanted to say so many things to him. He was an inspiration to me, even in prison, because I thought of his courage and his commitment to his sport."

I doubt there were many people impressive enough to make Nelson Mandela feel 'extremely apprehensive', but Muhammad Ali was one of a kind.

In an America that told him to obey and conform, 'The Greatest' always had his answer – which we decided to write on his tea towel and mug: