Thirty-five years ago, Father Sigitas Tamkevicius was detained and repeatedly interrogated at a KGB prison for protesting Soviet religious discrimination.
On Sunday, Pope Francis will visit the Lithuanian Catholic priest's cell in what is now a museum in central Vilnius to pay tribute to those who challenged the Soviet regime.
"When I was sitting in that cell deep underground, if someone had told me the pope would come here... that would have been incredible," Tamkevicius, now 79, told AFP.
"The pope's visit to this place and tribute to the sacrifice for freedom cannot be overestimated," he added.
After Lithuania regained independence in the 1990s, Tamkevicius was appointed an archbishop.
Back in the 1980s however, he was accused of spreading anti-Soviet propaganda for having founded and edited the Chronicle of the Catholic Church in Lithuania.
Founded in 1972, the underground periodical covered the repression of Catholics. In classic samizdat fashion, it was smuggled across to the West, where it was picked up by sources including Vatican Radio and Voice of America.
Arrested and imprisoned in 1983, Tamkevicius served time in Soviet labour camps, including a spell in Siberia, before his release.
"We thought that if we got more freedom for the church, it would also bring more freedom to Lithuania," he said.
"Everybody knew that the church was fighting not only for its own rights but also for the nation's rights."
Tamkevicius said he was heavily motivated by the then pope -- later saint -- John Paul II's public solidarity with the "silent Church" in countries where faith was discouraged at the time.
Dissidents in Lithuania and fellow Baltic states Estonia and Latvia were also encouraged by the fact that the Vatican had refused to recognise the Soviet occupation of the trio.
The Soviets had handed Tamkevicius a 10-year jail sentence. In the end he was freed after six, in 1989, during the so-called perestroika reforms instituted by Soviet president Mikhail Gorbachev.
But many of those detained decades earlier never left the Vilnius prison alive. Carved into its stony walls are the names of dissidents killed there under Soviet rule.
Vilnius estimates that more than 50,000 Lithuanians died in camps, prisons, and during deportations between 1944 and 1953. Another 20,000 partisans and supporters were killed in anti-Soviet guerilla warfare.
- Moral authority -
The pope will also pay tribute to Holocaust victims at the Vilnius ghetto memorial.
Nazi Germany all but obliterated the once-vibrant Jewish community of the capital, known as the "Jerusalem of the North".
"We feel honoured by the pope's visit -- no matter that we have different religions -- and appreciate that he will honour the victims exactly 75 years after the ghetto was liquidated," community leader Faina Kukliansky told AFP.
"I believe his thoughts will also be with the Christians who saved Jews, including those who saved my family."
Around 200,000 Lithuanian Jews died at the hands of the Nazis and local collaborators under the 1941-44 German occupation -- nearly the entire Jewish population.
Today there are only around 3,000 Jews left in the EU and NATO member state of 2.9 million people.
Lithuanian President Dalia Grybauskaite said church support for dissenting voices helped it preserve a strong moral position in the country.
"The church was one of our pillars of resistance, alongside our language, culture and songs," she told AFP.
"We see the difficulties and challenges that the church faces in other countries but we are glad it preserved moral authority here."
© 2018 AFP