Image copyright Supplied Image caption The couple's romance has played out in labour camps, prisons and under house arrest, with the Chinese state always a third wheel

Liu Xiaobo, a Chinese dissident and Nobel Peace Prize laureate, has spent years in prison for calling for political change in his country. For more than half of his marriage to Liu Xia, he has been imprisoned, and now he is dying of cancer. The BBC's Celia Hatton looks back at how the couple's love survived.

They fought to be allowed to marry each other. But when the government in Beijing finally backed down, permitting one of its unrelenting critics to marry his love, problems remained.

The camera that was supposed to take the couple's official marriage picture wouldn't work. The photographer was left scratching his head. Chinese marriage certificates aren't valid unless they contain an official portrait snapped at the scene.

So, Liu Xiaobo and and his would-be wife, Liu Xia, improvised. They found single photos of themselves and stuck them side by side. The makeshift photo was stamped and finally, they were married.

That was in 1996.

Getting married was a small victory for the couple. It gave Liu Xia the right to visit her new husband in the grim labour camp in north-eastern China where he had recently been imprisoned. Liu Xia made the 1,600km (1,000 miles) return journey from Beijing every month.

"The train to the concentration camp," she wrote in a poem. "Sobbing pass and running over my body/ Yet I still couldn't hold your hand."

Their wedding banquet was in the labour camp's cafeteria, a scenario that would prove to be symbolic. Throughout their intense romance, the Chinese government was a relentless and interfering third wheel, the uninvited partner providing a constant backdrop to their interactions.

By all accounts, Liu Xiaobo and Liu Xia were inseparable, except when they were forcibly parted.

Image copyright LIU XIA / HANDOUT Image caption Once an author and professor, Liu Xiaobo became a famous anti-government activist in China

Liu Xiaobo started as a brilliant writer and a beloved professor who was often invited to speak and study abroad.

In the spring of 1989, he was in New York City when he heard about the pro-democracy protests making their way to Tiananmen Square. He returned home to China at once.

Xiaobo helped spur on the protesters, as their calls for political reform rose to a crescendo, and then helped to negotiate with Chinese soldiers for many of the students to leave without harm.

It is still a state secret how many were killed by government forces in June 1989, but most agree the death toll would have been far higher without Liu Xiaobo.

That made little difference to the government.

Media playback is unsupported on your device Media caption A look back at the 1989 Tiananmen Square massacre

Days after the silence fell on Tiananmen, Xiaobo was placed in a secret detention centre. He stayed there for almost 20 months. When he was released, he had lost nearly everything, including his prestigious teaching job and his home.

It was then that Liu Xiaobo connected with the light of his life: an exuberant young poet named Liu Xia.

Image copyright Getty Images Image caption Liu Xia and Liu Xiaobo are well-known inside and outside China

"I found all the beauty in the world in this one woman," he reportedly told a friend.

Six years younger, she was already recognised as a gifted writer. Her close friend, the writer Liao Yiwu, said that back then, she was always giggling. Xia's high tolerance for alcohol was also legendary; she could drink her friends under the table. Xiaobo adored large meals, but would only drink Coca-Cola.

Liu Xia came from a privileged background, the daughter of a high-ranking banking official. She was expected to become a civil servant too, but had recently given up that stable life in favour of writing.

Against all odds, Xia's parents encouraged her relationship with Xiaobo, despite his political troubles.

'If someone is in jail, their family's life ends too'

In the early days, the couple tried to establish the semblance of a normal life. Xiaobo moved into Xia's apartment, not far from Tiananmen Square, and they made a life together.

Liu Xiaobo was under near-constant surveillance by security agents, who pressured him to stop writing about the need for democracy, to stop criticising China's one-party state.

"You must understand: If the government persecutes someone, the first thing they try to do is disturb their private life" explains the couple's friend, Tienchi Martin-Liao.

"They will separate the couple. If someone is in jail, their family's life ends too."

The couple never seriously considered having children, Tienchi says.

"I asked him once, 'Hey, why don't you have a child with Liu Xia?'" Tienchi continues.

"Xiaobo told me: 'I do not want that child, a son or a daughter, to see their father be taken away by the police'.

"He told me that. That is the reason why the couple never had children."

'I have never had a peaceful day since I am with you'

Tienchi worked as Liu Xiaobo's editor, spending hours on the phone with him. Xia would sometimes bring him soup while he was on the phone, and Tienchi would listen to him happily slurp it down.

Later, when Xiaobo was handed his final prison sentence, the one that would put him behind bars for 11 years, Tienchi switched to speaking with Xia, who often sobbed on the phone.

"Of course she loves him and she is willing to do everything for him," Tienchi explained. "And sometimes she complains. Not really complains but still she says, 'Well, I have never had a peaceful day since I am with you together.'

"Which is true, which is totally true. Which doesn't mean that she wants to leave him or anything like that. She just wants to emphasise how difficult and under what hard conditions their love connection to each other has survived."

Even when Liu Xiaobo was out of prison, the couple were rarely left alone for long.

"Because he has written so many socially critical articles, a lot of underprivileged people would go to his house," Tienchi Liao remembers.

"He doesn't even know them. They just knock at his door and ring the bell at his house and say, 'please help me, some injustice has happened to me'. And mostly, he would help those people."

Image copyright HANDOUT Image caption The couple, seen here in 2002, have only been able to live together for part of their married life as Xiaobo has been in and out of prison

Liu Xiaobo once recalled that even the pleasures of a birthday party were sometimes impossible.

He once told a Hong Kong newspaper, "at Liu Xia's birthday, her best friend brought two bottles of wine but they were blocked by the police from my home. I ordered a cake and the police also rejected the man who delivered the cake to us. I quarrelled with them and the police said, "it is for your security. Bomb attacks are common these days."

But Xiaobo didn't ever decide to stop his work, even when it interfered with his home life with Xia. And some of that drive he blamed on his concern for her future.

"Liu Xiaobo frankly explained that he wanted to take advantage of the energy that he still has," his biographer and close friend, the writer Yu Jie, wrote.

"So he could save up more money for Liu Xia, just in case one day something happened to him. At least Liu Xia would still be able to live without worrying about food and clothing."

Some intellectuals said he wrote too many articles, and some of them lacked polish.

Everything changed when Liu Xiaobo helped to draft and circulate Charter 08, the document calling for an end to China's one-party rule that would land him in prison.

Xia had always stayed away from Xiaobo's political commentary, but she told the filmmaker Ai Xiaoming that she knew Charter 08 heralded trouble.

"I saw it coming early on," she explained. "'From the time that the first draft of Charter 08 appeared in my home, to when Xiaobo threw himself into revising it, I just knew that something terrible was going to happen."

"Did you read it?" Ai asked her.

'You wait in the intangible prison of the heart'

"I had no interest in doing so," she answered. "But I knew there'd be big trouble. I tried to tell Xiaobo, but it was no use. I could only do what I'd done in the past - patiently wait for calamity to descend."

Before Charter 08 was officially released, Xiaobo was taken away. At his trial almost a year later, he was found guilty of trying to overthrow the state.

His last public statement, made to the court in 2009, ended with an acknowledgement to his wife.

He said: "Throughout all these years that I have lived without freedom, our love was full of bitterness imposed by outside circumstances, but as I savour its aftertaste, it remains boundless.

"I am serving my sentence in a tangible prison, while you wait in the intangible prison of the heart. Your love is the sunlight that leaps over high walls and penetrates the iron bars of my prison window, stroking every inch of my skin, warming every cell of my body, allowing me to always keep peace, openness, and brightness in my heart, and filling every minute of my time in prison with meaning.

Media playback is unsupported on your device Media caption Liu Xia was being detained in her own flat in Beijing - and the BBC was prevented from seeing her

"My love for you, on the other hand, is so full of remorse and regret that it at times makes me stagger under its weight."

It's unclear how much Liu Xiaobo knew about Xia's living conditions after he began his final prison sentence.

Shortly after he won the Nobel Peace Prize in 2010 she was placed under strict house arrest, confined to her small apartment in Beijing.

When speaking with the BBC in 2010, Liu Xia said she couldn't give Xiaobo any detailed information about her house arrest. "We were not allowed to talk about these things. We couldn't talk about these things. Anyhow, I thought he could understand me. I just told him, 'I live a life similar to yours'."

Image copyright Getty Images Image caption Liu Xia was put under house arrest, prompting protests in Hong Kong

"Originally I thought, when it just happened, that I would just be locked in for about a month or two. Time flies, now I've been locked for two years."

As the years under house arrest dragged on, Xia became clinically depressed.

She had intermittent access to a phone, but could only phone a few close family members. A group of police would take Xia to see Xiaobo on occasions, but those visits were closely watched by the authorities, who would halt conversations if too much was shared.

Liu Xiaobo was finally reunited with his wife only after it was clear that he was dying of liver cancer. After he received medical parole and was transferred to a hospital in northern China, he pushed to leave China for overseas treatment. For Xia's sake, sources told the BBC.

Image copyright Reuters Image caption Liu Xiaobo's situation is famous around the world; when Chinese President Xi Jinping visited Berlin last week, these protesters held signs calling for the couple to be able to leave China, and saying the countries' leaders preferred to talk about pandas than human rights

"He worries what will happen when he's gone," one friend explained. "He wants to take her out of China, and her brother too."

Tienchi's voice drops when asked about the future for Liu Xia after her beloved Xiaobo passes away. "We know that she is very ill, physically and psychologically. We are all worried he doesn't have much time to live and we are all worried afterwards what happens to her."

When Xiaobo is gone, Xia will have little left of him. In 2009, she admitted that even Xiaobo's poems and letters to her have all but gone.

"During Xiaobo's re-education through labour for three years from 8 October 1996 to 8 October 1999, I wrote him more than 300 letters and he wrote me 2-3 million words. After our home was raided several times, his writings generally disappeared.

"This is our life."

Image copyright Supplied Image caption Liu Xiaobo was diagnosed with terminal liver cancer and has been let out of prison

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