The spiritual leader of roughly 15 million Greek Orthodox Christians worldwide died Monday after battling with liver cancer over the past several months.
Archbishop Christodoulos, who was 69, died around 5:15 a.m. Monday (10:15 p.m. Sunday ET) at his home in Athens suburb, church officials told CNN. A meeting of the Holy Synod, the church's governing body, has been scheduled for 2 p.m. Monday to discuss the election of a successor.
According to church rules, the Holy Synod should set a date for the election of a new archbishop within 20 days of a leader's death.
The church body has declared three days of mourning and said that the archbishop's body will be placed on public display before his burial in a few days.
Prime Minister Costas Karamanlis paid tribute to the bravery the archbishop showed during his sickness in a statement released Monday.
Describing him as an "enlightened" cleric, Karamanlis praised Christodoulos as a "religious leader who reinforced the role of Orthodoxy in the world," and for bringing the church closer to the public.
Christodoulos was elected church leader in 1998 and is credited with reinvigorating the vast institution that represents 97 percent of Greece's native born population.
He was one of several leaders of national Orthodox churches across the world. Istanbul-based Ecumenical Patriarch Bartholomew I is the spiritual leader of the world's 250 million Orthodox Christians.
During his tenure, Christodoulos helped create church Web sites and radio stations, and frequently issued detailed checklists on how black-clad Orthodox priests should conduct themselves in public.
The church leader drew criticism from politicians who accused him of meddling in their affairs, angered by his vocal opposition to everything from homosexuality and globalization to Turkey's efforts to join the European Union.
But public criticism of the church leader quickly faded after news of Christodoulos' cancer spread, and prominent left-wingers visited him in the hospital.
Christodoulos traveled to the United States in an unsuccessful attempt to get a transplant. He declined hospital treatment in the last several days.
Christodoulos is survived by one brother. Funeral arrangements were to be determined at the meeting of the Holy Synod on Monday.