VATICAN CITY -- Sharing lunch is rarely historic, except perhaps when the two people eating are a pope and his predecessor.
On Saturday, the pope emeritus, Benedict XVI -- who broke church tradition by resigning rather than dying in office -- ate with Pope Francis at Castel Gandolfo, the hilltop villa where he is living, while a scrum of reporters waited outside for any scraps of news about how the meeting went.
Vatican officials gave no word about what the past and present leaders of the Roman Catholic Church discussed, and even rebuffed questions about what they ate. They did, however, paint a picture of a seamless transition: when Benedict offered his successor the "place of honor" during shared prayers, the Vatican said, Francis demurred, suggesting that they kneel side by side as "brothers." Their first embrace, a spokesman said, was "wonderful." Both wore white, the traditional color of the pope.
But the reality of a pope and an emeritus pope living in his shadow will probably be more complicated, a fact driven home with the recent publication in an Italian gossip magazine of paparazzi-style photos of the 85-year-old Benedict, clad in white, strolling with his personal secretary through the private gardens of his temporary home at Castel Gandolfo.
The photographs were a vivid reminder of the uncharted territory the Vatican has entered, and the potential trouble it could bring.
Virtually every day highlights the strangeness of the circumstances and raises new questions about what the relationship between the two men will be, especially when Benedict moves back to a residence at the Vatican that is being renovated.
One Italian newspaper called the lunch on Saturday "a rehearsal for cohabitation."
The last time that any two popes would even have had the opportunity to meet was in 1294, when Boniface VIII succeeded Celestine V, who abdicated after a disastrous five-month papacy that laid the foundation for the Great Schism. And that relationship was far from smooth: Boniface eventually threw Celestine into prison.
During this transition, the new pope, the cardinals and the Vatican have gone out of their way to express affection and gratitude toward the pope emeritus. But each time they do, it does more to deepen the complexity of the relationship than to clarify it.
Francis telephoned Benedict immediately after his election on March 13, before appearing on the balcony at St. Peter's Square, where the new pope publicly asked the crowd to join him in praying for "our bishop emeritus." On Tuesday, after the installation ceremony on the feast day of St. Joseph, Francis called Benedict, the former Cardinal Joseph Ratzinger, to wish him a happy name day.
There has been an unexpected amount of attention lavished on a man who had pledged to live out his days "hidden from the world." As Francis' papacy lengthens, the reasons for Benedict's eventual seclusion inside the Vatican become clearer.
It is, Vatican experts said, a solution that not only provides a secure environment for Benedict, but also effectively avoids setting up a power center rivaling the Vatican. And it discourages any following that could coalesce around the pope emeritus in a church mindful of painful schisms that have shaken it at important moments in its history.
Now that resignation from the papacy has been resuscitated as an option after 600 years, the Vatican is no doubt concerned about setting precedents, said Alberto Melloni, the director of the John XXIII Foundation for Religious Studies in Bologna.
"You couldn't have the pope in a German convent where he could become a pole of attraction for those faithful reluctant to accept his resignation," Mr. Melloni said.
In a few weeks, Benedict will move into a nondescript convent not far from the sumptuous apostolic palace where he lived as the leader of the church.
Already, canonical experts have raised questions about the correctness of Benedict's adopting the title of "pope emeritus." Writing in La Civiltà Cattolica, a Jesuit magazine, the Rev. Gianfranco Ghirlanda, a former rector of the Pontifical Gregorian University, argued that a more appropriate title would be "bishop emeritus of Rome, like any other diocesan bishop who steps down."
The Vatican has played down the novel accommodation. To have the pope emeritus "present, near, discreet" will provide a "great enrichment" for the new pope, the Vatican spokesman, the Rev. Federico Lombardi, told reporters recently.
But having a former pope hovering in the background has proved to be disconcerting to some, not least the pontifical staff. The potential for divided loyalties has already provided fodder for the Italian news media.
Benedict's personal first secretary, Archbishop Georg Gänswein, has been living at Castel Gandolfo with his old boss. But he is also the prefect of the pontifical household, and he has been a discreet fixture at Francis' first public outings, including Saturday's lunch. He has now been described in the Italian news media as the "ferryman" between the two pontificates.
Writing in La Stampa, the Vatican correspondent Giacomo Galeazzi described Archbishop Gänswein as tearful and distraught when the seals placed on the doors of the papal apartment when Benedict resigned were removed, opening it to his successor.
"Once inside, the memories must have overwhelmed him," Mr. Galeazzi wrote.
Benedict's higher-than-anticipated profile has perplexed some. "It is baffling that the pope should appear in public as he did before; it's incomprehensible," said Massimo Franco, a commentator for the newspaper Corriere della Sera, after the photographs appeared in the magazine Chi.
"I understand that it will be difficult to regulate, but the Vatican will have to establish some rules," Mr. Franco said.
The Vatican has rejected any prospect of meddling by Benedict. But concern remains among some cardinals, Vatican officials and church experts.
"There is a duality, and even if the old pope says he will retire from the world, he will be an awkward presence," said Roberto Rusconi, a church historian at Third University of Rome.
But he dismissed the possibility of a new schism like the one that occurred with the death of Pope Gregory XI in 1378. Afterward, one pope lived in Avignon, France, and another in Rome. Such divides were fomented by secular rulers, he said, with the dueling popes each claiming legitimacy.
Even so, he said, better to keep the pope inside the Vatican -- in its own way a prison of sorts, like any cloistered convent -- because not everyone might resist asking the old pope's opinion. Professor Rusconi added, "That just can't happen."
Benedict's decision to remain secluded in the Vatican was also dictated by a desire to preserve his privacy in a modern media age of unquenchable appetite, he said.
"Just think of what Kate Middleton goes through every day," Professor Rusconi said of Prince William's pregnant wife. "Everywhere the pope would go, he would be assailed by journalists; he'd have no defense," as the pictures of the pope emeritus in Castel Gandolfo showed, he said.
On Saturday, Father Lombardi's recounting of the popes' meeting appeared to try to address lingering concerns.
Although Father Lombardi said he could not release much information of what he called "a private encounter," he did offer this guess at what happened. Francis, he said, was likely to have thanked the former pope for his pontificate and Benedict would have renewed his unconditional obedience to the new pope.
This article originally appeared in The New York Times.