The day Johnny Cash went to prison

Fifty years ago, Johnny Cash walked through the gates of Folsom Prison. Not because he'd shot a man, but because others might have.

"Hello, I'm Johnny Cash," his deep and playful voice whispers at the start of the live recording, preluding the opening notes of one of his most famous songs.

That moment - Cash standing guitar in hand in front of the prison cafeteria - would later be seen as a turning point in both his career and his life.

Of all the great records released in the Sixties, from The Beatles' Sgt Pepper to Dylan's Blonde On Blonde, Johnny Cash's At Folsom Prison remains to this day the most personal and most mythologised.

Perhaps because Cash was such a mythical character himself - The Man In Black, the pilgrim, the preacher.

"A walking contradiction" was the agreed epitaph. And it suited him.

Cash toured in prisons but was never sentenced, it took him half his life before he walked the line.

He was his own man, never mincing his words or minding his actions. Struggling with drugs and women, he cultivated an outlaw image which ultimately helped him revive his career and turn his life around.

The flipping point, music historians would agree, was 13 January 1968, when Columbia Records finally let him record live inside a California jail.

"It was the moment that he came into the light," his daughter Rosanne Cash would recall 40 years after.

"It's a paradox, but it's true. When I think about my dad's life and I think about that moment, that's when there's a kind of force, when he embodied who he really was.

"And that's light, no matter how much darkness is in it."

At Folsom Prison became one of the best-selling live albums of all time, reaching the top of the country charts and a defining moment for Cash.

From that point on, he would be the preacher of the poor and the downtrodden, the singer of thieves and murderers and an advocate for prison reform.

"He was just so magnanimous during that time," Rosanne said.

"He was straight for several years after that. He got really healthy."

After Folsom, Cash decided to tour other prisons.

He brought with him his Folsom Prison Blues, claiming he had "shot a man in Reno just to watch him die"; and his Cocaine Blues, where he tells about the time he "took a shot of cocaine and shot my woman down".

But these were just characters, imaginary depictions of the inmates he played for.

In reality, Cash had his mugshot taken for smuggling a bunch of pills across Mexico. He was arrested but never convicted.

And so it was throughout most of his career, inadvertently turned into a myth while trying to celebrate others.

During his prison years, he met with inmates and actively tried to help them. Glen Sherley was one of Folsom's convicts when Cash first performed there, two years before returning to record the album.

Cash grew fond of Sherley, who wrote and played songs, and decided to take him under his wing, welcoming him to the band upon his release.

"I didn't get how my dad let all of these people come to him. People would come backstage and audition for him so that he could call up somebody from the record label," his daughter said.

Cash would later be forced to fire Sherley for threatening one of his bandmates. Sherley eventually killed himself and Cash paid for the funeral.

"I think that honestly my dad had an inflated sense of his own power about his ability to change some of these men's lives, and I think it got him into trouble," she said.

For 10 years he was the inmates' personal Jesus but, before that, he had already been cast in a different role.

After paying a $1,000 fine for his pill smuggling, he left the courthouse in El Paso in 1965 with his then wife Vivian at his side.

A photo of the couple was taken and published in a white supremacist newspaper, accusing Cash of being married to an African-American.

"Johnny and I received death threats, and an already shameful situation was made infinitely worse," Vivian recalled in her memoir I Walked The Line.

For a southern legend in the early Sixties to be seen as racially tolerant was a problem, and Cash was harassed and boycotted.

But what seemed like a troubled time for Cash ended up making him a symbol of tolerance, and the start of a new kind of country which would see stars like Willie Nelson bring together redneck conservatives and liberal hippies.

The line Cash walked was between myth and reality, good and evil, instinct and faith.

It was a minister who invited him to perform at Folsom, the Reverend Floyd Gressett, something reporter Gene Beley would recall as a weird vision, seeing the outlaw singer being so close to a man of the cloth.

"It seemed so incongruous," he said.

But as Cash grew older, his faith became stronger, and so did his lyrics. You can hear his Christianity evolving throughout his later albums - his black cloth reminding us less of an outlaw and more of a preacher.

Now, 50 years later, listening to his performance live at Folsom Prison, I find myself trying to decipher the artist behind the sound.

Listening to the grain-filled recording of a legend who had, at the time, no idea where the rest of his life would take him.