Francis referred to that historic trip during his opening speech before Romanian government authorities and his subsequent meeting with Patriarch Daniel, the head of the Orthodox Church. John Paul's 1999 visit to Romania, just 10 years after the fall of the Berlin Wall, was the first by a pope to a majority Orthodox country since the Great Schism divided Christianity in 1054.
It was marked by an extraordinary welcome for a Polish pope who helped bring down communism and included spontaneous chants of "unity, unity" from the crowds. "This is already unity," Francis told Daniel on Friday.
"We need to help each other not fall into the seduction of a culture of hatred, an individualistic culture that may not be as ideological as during the atheist persecutions, but is still persuasive," he said.
It's the latest of Francis' foreign trips to poor countries where Catholics are a minority. In Romania, they are a divided minority between two Catholic rites, Roman Catholic and Greek-Catholic Francis warned that all Romanians must come together even more now to confront today's challenges, noting the huge numbers of people who leave the country each year in search of jobs, depopulating entire villages and weakening the roots of Romanian culture.
"Only to the extent that a society is concerned for its most disadvantaged members, can it be considered truly civil," he said. Key moments during Francis' trip are his Mass for the largely Hungarian-speaking Roman Catholic faithful at the country's most famous Marian shrine, Sumuleu Ciuc, in eastern Transylvania. He will also beatify seven Greek-Catholic bishops who were martyred during communist rule, when Catholics were brutally persecuted.
"I'm coming to you to walk together," Francis said in a video released on the eve of his trip. In a sign of their unity, Francis and Patriarch Daniel recited the Our Father prayer in the Orthodox Cathedral, a towering new construction funded in part by a $200,000 donation by John Paul when he visited in 1999.
Vatican spokesman Alessandro Gisotti stressed that while the two religious leaders physically prayed in the same place, they didn't pray together, an important distinction for many Orthodox. Ordinary faithful were on hand for the chant-filled service, in sharp contrast to Francis' recent visit to Bulgaria, when he was allowed to pray in the Orthodox cathedral in Sofia, but alone.
In 1999, John Paul agreed to Orthodox demands that he visit only Bucharest and not Transylvania, where most of the country's Catholics live. In many ways then, Francis is fulfilling the itinerary that John Paul wanted to complete.
As then, the issue of confiscated property of the Catholic Church that was given to the Orthodox during communist rule remains a sore spot in relations. Gisotti said there were no plans for any public discussion of the dispute but didn't rule out private talks.
"We live in times of peace and understanding, but we wish these relations (between churches) to become better," said Francisc Dobos, spokesman for the Bucharest archbishopric. "We should not be afraid of one another, we should trust one another. This visit should make us become better Catholics and better Orthodox and in the end, better citizens."
Winfield reported from Rome.