(CNN) The sun had already set when the woman with long gray hair descended the steps to the same prison gate she had passed through all those years ago.

Mahvash Sabet had been behind bars for an eternal decade, and on this evening, she was leaving Tehran's Evin Prison without money or possessions or anyone waiting for her.

Iranian authorities released Sabet from her jail cell a day ahead of schedule at a little after 5 p.m., the deadline for prisoners to make their last phone calls of the day. The move was deliberate, she believes, to keep her homecoming quiet and largely removed from media glare. She had become, after all, internationally known.

Outside the prison gate, Sabet asked to borrow a passerby's phone, then waited patiently for the 90 minutes it took her husband to cross Tehran in rush-hour traffic.

She had been arrested, interrogated and tortured for her faith -- she is Baha'i, a religion the Islamic Republic of Iran considers heresy. She and six other members of an informal Baha'i council known as the Yaran, or Friends in Iran, were arrested in 2008.

Her Baha'i beliefs in peace, altruism and humanity were, undoubtedly, instrumental to Sabet's perseverance in prison. But she also relied on something else: poetry.

"Writing," she says, "became my means of survival."

She scribbled her words on paper napkins and towels and shoved them into pockets and purses during precious "contact" visits with family, when they were not separated by the usual thick glass.

The words she managed to get out of prison described a place of bleakness but one that could not break the human spirit.

Author Bahiyyih Nakhjavani reads a statement from Mahvash Sabet at a PEN International ceremony honoring Sabet's poetry.

They were words that recently earned Sabet recognition from English PEN, the founding center of PEN International, which promotes freedom of expression. Poet Michael Longley, winner of this year's PEN Pinter prize, named Sabet as the 2017 International Writer of Courage.

"Her imagination is rhapsodic. Her poems want to soar," Longley said at a ceremony ipn London.

He called her incarceration a "sin against the light" and then, quoting William Blake, said: "The power of dictators to silence and imprison writers continues to 'put all heaven in a rage.'"

Sabet walked free of Evin Prison on September 18, the eve of President Donald Trump's speech to the United Nations, which focused in part on Iran. But, really, she had escaped prison long ago, when she began writing.

What are they doing to us in this perilous place,

this prison of loss?

But what can they do to a handful of dust

in the middle of chaos?

If they cut open our veins, red tulips will blush

like blood in the fields.

If they padlock our lips, the mouths of a thousand

spring buds are unsealed.

'Where's the life in your roots gone?'

Before Shiite clerics took over Iran, Sabet lived another life.

Born Mahvash Shahriyari in the small city of Ardestan, about 225 miles south of Tehran, she moved with her family to the capital when she was in the fifth grade.

She earned a degree in psychology but also taught and became a principal in several schools. She had always loved writing and was good with words, say those who know her, and for a while she played a role with the National Literacy Committee of Iran.

Sabet was a teacher and principal before Iran began persecuting the Baha'is.

She fell in love with Siyvash Sabet and the two married in 1973. They had a son, Foroud, and a daughter, Negar.

But the life she had envisioned ended with the Islamic revolution.

The Baha'i faith is monotheistic and focuses on the spiritual unity of humanity. It was founded during the 19th century in what was then Persia and has millions of followers across the world, including 300,000 in Iran.

But Iran's Shiite clerics view the faith as blasphemous because its founder, Baha'u'llah, declared himself to be a prophet of God. Muslims believe the Prophet Mohammed was the last prophet of God. And so, since 1979, life for Baha'is in Iran has deteriorated.

Iran banned the religion, and the Baha'is -- the largest religious minority in the country -- have faced persecution in all aspects of life. Baha'i cemeteries have been desecrated; their marriages are not recognized.

The Iranian government, says Amnesty International, routinely denies the Baha'is "equal rights to education, work and a decent standard of living by restricting access to employment and benefits."

Sabet was fired from her job as principal and permanently barred from public education. She eventually became a director of the Baha'i Institute for Higher Education, created to help Baha'i students barred from higher education in Iran.

On March 6, 2008, the Ministry of Intelligence and National Security arrested Sabet and jailed her for more than two years without a proper hearing. Eventually, a revolutionary court convicted Sabet and the six other Baha'i leaders and condemned them to 20 years behind bars, although later the time was reduced to 10 years. The charges against them included espionage for Israel and spreading propaganda against the Islamic Republic.

It was a verdict that Amnesty International called a "damning manifestation of the deeply rooted discrimination against Baha'is by the Iranian authorities."

One of Sabet's lawyers, Mahnaz Parakand, recalls her first encounter with Sabet in February 2009. Sabet was handcuffed to Fariba Kamalabadi, another of the Baha'i leaders.

The two women did not complain or speak of themselves, Parakand recalls, but she could tell from the color of their skin that they had been deprived of daylight and fresh air.

"However, despite all their hardships, their will remained unbroken and they were determined to give up their lives, if necessary, for their beliefs," Parakand would later write.

About the same time, Iranian authorities arrested American journalist Roxana Saberi and imprisoned her in Evin for 101 days. Saberi shared a cell with Sabet and Kamalabadi.

"They taught me to, as they put it, turn challenges into opportunities -- to make the most of difficult situations and to grow from adversity," Saberi wrote of their encounter.

"We kept a daily routine, reading the books we were eventually allowed and discussing them; exercising in our small cell; and praying -- they in their way, I in mine. They asked me to teach them English and were eager to learn vocabulary for shopping, cooking and traveling. They would use the new words one day, they told me, when they journeyed abroad. But the two women also said they never wanted to live overseas. They felt it their duty to serve not only Baha'is but all Iranians.

"Later, when I went on a hunger strike, Mahvash and Fariba washed my clothes by hand after I lost my energy and told me stories to keep my mind off my stomach. Their kindness and love gave me sustenance."

Evin has been home to thousands of political prisoners in Iran. Many wallowed in grief. Many broke. But not Sabet.

She had been confined to a 13-by-16-foot shared cell in Evin's Section 209, a ward notorious for housing prisoners of conscience. The small windows were covered by metal that let in hardly any light. Often, she slept on a cold cement floor, even in the midst of harsh winters. She was subjected to nightlong interrogations and worse: torture and solitary confinement.

After her release, I wrote to Sabet, asking about her imprisonment, her poetry and how she survived.

"A prison does not merely consist of high walls and barbed wire. The effects go far deeper and are much more complex than external barriers," Sabet said in a translated and emailed response to my questions.

She says her confinement cut her off from everything, even her own senses of light, taste, touch and sound, to the point that the sensory deprivation began turning her into a vegetable.

"They leave you into this limbo state and simply feed you to keep you alive," she says. "And all through this time, they interrogate you. They throw false charges at you over and over again. They accuse you, threaten you, abuse you, curse you, humiliate you. And you have to endure it all knowing that this could lead to further charges, more indictments, longer imprisonment ahead."

But there was something else that was even harder to endure, she says.

"Worse than this was that they wanted me to forget who I was. They wanted me to forget what I believed, forget my identity."

Sabet searched for signs of hope in the smallest things, a sparrow taking flight or a thistle growing out of the pavement. And she began writing them down.

And I said to myself,

'Are you less than a weed then?

Where's the life in your roots gone?

Where's growth in your leaves? Your stem? No stirring in you at all? For shame!

And at that I felt a surge of the sap

Of spirit blaze within.

'They cannot take from me what I shall never lose'

At first, Sabet says, she wrote poems for her family. She wanted to cheer them up.

"I didn't want them to suffer for me; I wanted them to stop grieving for me," she says.

"But soon, poetry began to lighten my own heart, too. I found that I could express my deepest feelings through poems. They could contain my misery amnd my suffering, my anguish at being separated from my friends and family, and in addition to recording painful moments of crisis, they became the place where I could record my little victories."

She discovered she could put her anger and grief away if she expressed them in a poem. Her words allowed her to forget heartbreak and sorrow, overcome disappointments. They cleansed "the rust off my heart and recover the strength of my soul," she says.

Why is it that despite its reels and shakes

the topsy-turvy world here cannot cause

this throbbing heart of mine to ache?

... If I have not died here it is because

they cannot take from me what I shall never lose.

But she also wrote so that she would remember her experiences, she says. She kept a pen and notebook with her and wrote every single day. In prison, poetry became Sabet's best friend.

... And that is why I need a balm to perfume

this camphor-tasting bread.

A light to cast on these yellowed faces.

A breath to lift these heads.

Sabet at her Tehran home in a recent photograph taken after her release.

'And I witnessed it'

Sabet's lyrical verses, taken out of Evin by visitors, reached a relative, novelist Bahiyyih Nakhjavani, in the spring of 2011.

Nakhjavani's parents, also prominent Baha'is, left Iran in 1951 and raised their daughter in Uganda and the United Kingdom. In 2003, Violette and Ali Nakhjavani retired to a town on the outskirts of Strasbourg, France, and that is where the family first received an envelope containing a handful of Sabet's poems, typed out in Persian.

Violette read them out to Bahiyyih, whose knowledge of the language is limited. Soon, more poems arrived and together, mother and daughter translated and recast each one so that it made sense as poetry in English.

It was a labor of love, so touched were they by the power of Sabet's verses. They were, Bahiyyih Nakhjavani tells me over the phone, "delicate and without recrimination."

"Like many Persians, versifying was in [Sabet's] blood but she had never considered herself a poet," Nakhvajani says. "Her words made me weep — not just because of the terrible conditions she described, but because of her compassion.

"She was simply trying to lift her spirits and those of others as high as she could above those walls."

There was one poem that especially touched the Nakhjavanis -- about a woman who died in prison. Sabet had seen a prison guard stuff the woman's body in a bag, like a dried-up branch of pine needles.

All they said was -- well,

The poor thing is free at last --

And I witnessed it

Her bundle of things, so frail

An ant could have carried it off like a grain of wheat --

And I witnessed it.

Her food a crumb of bread, so small,

That a worm in the water could have swallowed it --

And I witnessed it.

"My mum said, 'We have to get this out,'" Nakhjavani says.

"They put this woman in a bag and carried her off. Nameless. She had no significance to anyone in the world but was immortalized by the compassion of a witness -- that was Mahvash."

As challenging as it was for Nakhjavani to take on a Persian poetry translation project, she felt compelled. Her mother died a year after they began, so her father became her translator.

"I had to do these for the nameless woman. For my mum," Nakhjavani says. "Mahvash is bearing witness. For all the women who have died nameless in the world."

"Prison Poems" was published in 2013. It contains about 70 of Sabet's works.

"This project humbled me," says Nakhvajani. "If I were in her situation, I don't think I would have had this courage."

In this way, Sabet's words survived prison walls and then transcended the barriers of translation, interpretation, reconstruction and appropriation into another language. In this way, Sabet's words became known to the outside world.

Although you're rooted to your feet

You long for the sky;

Although you're sister to the dust

You yearn to fly high

Sabet, right, with the other six Baha'i leaders who were arrested and jailed for 10 years.

'Stay near that we may be reunited'

On that September evening when Sabet was no longer a prisoner, she emerged from Evin with a purple head scarf. She had never cut her hair behind bars and it had turned from a brown shoulder bob to silvery waist-length locks.

Doubt and distress filled Sabet on the inside. Anxiety sliced away the joy of seeing her loved ones again.

Nakhvajani saw the photographs from the night of Sabet's release and was struck by her grace after so many years in prison. Her first public statement centered not on her own hardship but on her wish for her prison companions to be freed.

Then she climbed into a car and drove into Tehran with her husband.

Home was beautiful

With everyone busy doing things.

Your prayers there tasted of eternity.

Yet, everything felt new.

She didn't know what to do with the money her husband gave her. She was dazzled by the new technology that had taken over during her time behind bars. She felt fearful of open places; even in her own home, she did not feel safe. Were there cameras detecting her every move? Was someone watching as they had in Evin?

Her family had a new house and it seemed as unfamiliar as a hotel room, though occasionally she spotted remnants of her old life: a photograph, a tray. But mostly, she recognized nothing.

"Did we have this before?" she asked. "Where did this come from?"

"Don't you remember?" her family members replied.

But she didn't.

The dresses in the cupboard were mostly new, but when she did recognize one, it filled her with sadness. It was a reminder of the past she was forced to leave behind.

"I had to forget all my old habits," she says. "I had to adapt myself to living on a thin blanket on the floor. That was where I did everything. I had to sit on that blanket, eat on that blanket, read and write and say my prayers on that blanket and finally, sleep on that same blanket."

Yet, she blamed no one for her ordeal.

"I am a Baha'i and Baha'is are encouraged not to think of people as enemies," she says. "They are urged not to harbor resentments or bear grudges towards others. ... They should strive to see something they love and to respect every soul.

"Do I strive for this ideal? I do not always succeed, but I try."

While she was in Evin, PEN decided to honor Sabet as the 2017 Writer of Courage. She was deeply touched by the recognition but did not know then that she would be free to send a statement on the night of her honor.

Nakhjavani traveled to London to read it on Sabet's behalf.

"Ten years of my life has just passed behind bars and I, as a renter of the world, I find myself given this incredible award. It is a wonder to me. And a mystery.

"Coming back into the light after these 10 long years in darkness has not been easy. The changes I see all around me are truly astonishing. The pace of life is overwhelming. But the hardest thing for me is to know that even though I am walking free, many other friends and colleagues still remain behind bars. So in the midst of my wonder, I am filled with anguish. I am torn between joy and sorrow at this moment. ..."

Sabet was recently reunited with Fariba Kamalabadi, another Baha'i leader released from prison.

Now, as it was in Evin, poetry warms Sabet's heart. She is filled with "unutterable joy" when she meets those who have read her verses and understand what she was trying to say.

A couple of weeks after the PEN ceremony, Sabet was reunited with Fariba Kamalabadi, the second of the seven Yaran to be released. The Baha'i International Community expects the release of the other five leaders soon.

One of Sabet's poems paid tribute to her former cellmate:

To my dear Fariba

How can I,

without your mirror,

know who I rightly am?

Stay near that we may be reunited

and forever remain.

Every morning

I feel myself melting,

flowing and coming alive

as I dive into the crystal clear springs

of your heart's waves.

Sabet is no longer in prison but she is not free.

Not in Iran, where persecution of the Baha'is not only continues but has worsened, according to a report published by the Baha'i International Community.

"The Baha'is in Iran continue to face daily pressures aimed at eradicating them as a viable entity in their own country," says Diane Ala'i, the organization's representative to the United Nations.

About 100 Baha'is remain languishing in Iranian prisons, all of whom, the Bahai's say, are there solely because of their religious beliefs.

Sabet thinks of them as she tries to put back the pieces of a life interrupted. She thinks of the prisoners inside Evin. Of those who survived. And those who did not.

Or perhaps someone took her to see God

Up in the higher realms somewhere.

And maybe He gave her a shelter there,

A threshold she might call her own,

And offered her just enough shade for joy,

For a mouthful of peace, for the taste of love.

And maybe God, at least, believed in her sufferings.