Watch Ivan Watson's insightful documentary on the patriarch's plight on CNN International's "World's Untold Stories." Check out all the broadcast times and some of our best videos and past episodes at our new website
Istanbul, Turkey (CNN) -- Ecumenical Patriarch Bartholomew is the living embodiment of an ancient tradition. From his historic base in Istanbul, Turkey, the 270th Patriarch of Constantinople claims to be the direct successor of the Apostle Andrew.
Today he's considered "first among equals" in the leadership of the Greek Orthodox church, and is the spiritual leader of 250 million Orthodox Christians around the world. But few of them are in his own home country.
"We are a small Christian minority," Bartholomew laments.
"We have suffered because of Greek-Turkish confrontation, struggle, and a lack of mutual trust and confidence. And that is why we lost most of our faithful."
Turkey's once-flourishing Greek community is fading away. The country is predominantly Muslim and led by a secular government that's had a complicated relationship with the patriarchate.
If Turkish laws, demographics and attitudes aren't changed, Bartholomew could ultimately be the last Patriarch of Constantinople.
"We are not all in despair for the future of our church," Bartholomew said. "It is not easy, but it is not impossible."
The Turkish government can veto any candidate put forward for the position of patriarch. And it requires the patriarch be a Turkish citizen. Bartholomew is, but most of those best qualified to succeed him are not.
So the government has proposed offering Turkish citizenship to Orthodox archbishops overseas. Several have applied; so far, none has been approved.
The Turkish government also refuses to recognize the title Ecumenical Patriarch, or Bartholomew's role as an international religious leader.
Officially, he is viewed as a local bishop who leads a shrinking community of a few thousand Greek Orthodox citizens. Yorgo Stefanopulos is one of them. "I am a curiosity now in Turkey," he said. "We used to be a minority; now we are a curiosity."
Stefanopulos is an outspoken leader of Istanbul's Greek community. About 50 years ago, that community numbered more than 100,000. Today, it's probably less than 3,000.
He insists that decline was not accidental. Instead, he blames the Turkish government. Decades ago, he said, they targeted ethnic Greeks with nationalist policies, like wealth taxes, property seizures, and campaigns to speak only Turkish in the streets.
Then there was the pogrom in 1955: riots directed against Greeks and Greek-owned property. The violence was later found to have been orchestrated by Turkish authorities.
As a result, Greeks left Istanbul in droves. "The Turkish government somehow managed to do a bloodless ethnic cleansing," Stefanopulos said. Today's Turkish government says those events are from the distant past, and they're now looking ahead to reconciliation.
"Turkey is going through a period of transition," said Egemen Bagis, the country's Minister for European Union Affairs. "Turkey's becoming a much more democratic, much more prosperous, much more transparent society."
Yet, the government has resisted calls to reopen the patriarchate's main school of theology.
For more than a century, the Halki seminary educated future Greek Orthodox bishops, theologians and patriarchs, until Turkey's highest court ordered it closed in 1971. Since then, it's remained empty, worrying former students like theologian Satirios Varnalidis.
"We want to reopen this school so that we can provide new priests to the Ecumenical Patriarchate," Varnalidis said. "Otherwise, in a little while our community just won't have any more priests."
For years, Turkish Prime Minister Recep Tayyip Erdogan has talked of reopening the school. Bagis insists the government is still working on it.
Despite these difficulties, Patriarch Bartholomew is heartened by new signs of hope that his community and his church will survive.
"We have many young people from Greece who want to come and be established in Turkey," he says. "This is an opposite current than before."
Haris Rigas is part of that trickle of fresh immigration, which offers perhaps the best hope of reviving Istanbul's Greek community. "The minute I came I was in love with the city and felt that I had to live here," he said.
Rigas has been studying the city's indigenous Greek community. He's also a musician in a band that plays Rembetiko, a genre of old, mostly Greek, folk songs. His studies and his music are focused on the preservation and promotion of Greek culture.
"The only way for the community to survive is to attain a degree of visibility," he said. "They've played an important historical role in this city throughout the centuries, and I think they should still do it."
Earlier this month, the Turkish state and the Ecumenical Patriarchate made a historic step towards reconciliation.
Thousands of Orthodox Christians gathered for a prayer service at the ancient cliffside monastery of Sumela, near Turkey's Black Sea Coast, on August 15. Patriarch Bartholomew conducted a divine liturgy, the first Christian service of its kind at Sumela, in more then 80 years.
Even if Istanbul's Greek community makes a comeback, some fear that the patriarchate itself may not last much longer, due to demographics and lingering suspicion from the Turkish government.
And the patriarch remains hopeful and resolute. He rejects conjecture that he could be the last Ecumenical Patriarch of Constantinople.
"Absolutely not," Bartholomew insists. "We trust a divine providence, and the guarantee given to us by our Lord himself, that the church can survive.
"This is our faith, this is our conviction, this is our hope, this is our prayer. And all the rest we leave at the hands of God."
CNN's Ivan Watson and Yesim Comert contributed to this report