At dawn in the Dengchi Valley, deep in the wild mountains of south-west China, local farmers have already been walking for hours through the darkness, bundled up in padded cotton jackets and woollen caps.
By Holly Williams
They have come to meet at the Dengchi Valley Cathedral, an old wooden church built over 150 years ago by French Jesuit missionaries in the province of Sichuan, and home to a flock of more than 1000 Chinese Catholics.
Father Benedict Yang is the cathedral's energetic young priest. He has just graduated from a seminary in the city, where he learnt what would shock Catholics in other parts of the world - that the Dengchi Valley congregation is part of the Communist Party-controlled Chinese Patriotic Catholic Association, an organisation whose head is not the Pope, but the Chinese Government.
The Communist Party is fearful of foreign influence, and jealously maintains control over all organised groups within China. So Father Benedict and his flock are not allowed to have any contact with the Vatican.
In his sermon, Father Benedict must preach the use of contraceptives, and explain to his flock that former leader Mao Zedong has gone to heaven - anathema to believers elsewhere in the Catholic world.
Father Benedict struggles to explain the contradictions of being a Catholic in China.
"Our government respects Christians. But Catholics must be united with all other Chinese, and co-operate with the government. Religion must be practised according to the law," he said.
It has not always been so for China's faithful.
Openly practising Catholics must do so in state-approved churches
Eighty-six-year-old He Defang has ploughed the hillsides of the Dengchi Valley all his life. His face is tanned and crinkled.
Mr He remembers a time when religion was not about politics - a time before 1949, when the communists came to power.
"The church was built by Father David, then came Father Lai, then after him father Liu, then Wang, Nian, Yao, Chen, Yuan and Father Yi. After him came the revolution," he said.
With revolution came a new, atheist regime - one that frowned on all religious belief.
Through their supporters in the West, underground Catholics tell stories of constant harassment
And there was worse to come. In the 1960s, Chairman Mao launched his Great Proletarian Cultural Revolution - 10 years of chaos and violence led by teenage Red Guards. They sought to stamp out anything traditional or religious, and they targeted Christians.
He Defang remembers the day the Red Guards appeared in his valley.
"They came to the church and smashed everything up. Then they occupied the church, took the priest away, and sent him to a labour camp. During those days none of us could admit our religious beliefs. We had to pray in secret," he said.
The hysteria eventually passed, and in the 1980s He Defang and his family were allowed to start practising again.
Now Mr He's children, grand-children and great-grand-children are all free to read their bibles, but that freedom has come at a price - Communist Party-control and isolation from Rome.
Not all of China's Catholics are willing to accept the compromise.
The country is also home to several million underground Catholic believers, who are in contact with the Vatican, and who have their own, secretly-ordained bishops.
It is a high risk decision. Through their supporters in the West, underground Catholics tell stories of constant harassment. In October the Church reported that police raided a retreat and arrested 12 priests and seminarians.
Last year the authorities allegedly bulldozed a church built by the underground movement.
Members of China's secret Catholic Church who I contacted were too frightened to talk.
Father Benedict did not want to discuss the underground Church either, but he did tell me that he prays for the day when China's Catholics are reunited - with each other, and with Rome.
"All Catholics in China are hoping for this, and with God's help and blessing and the government's help we believe that good relations can be established between China and the Vatican," he said.
Until then China's Catholics must spend another Christmas divided, and the faithful of Dengchi Valley must keep their belief alive, isolated from their brethren around the world.