Before Benedict XVI
resigned last month, the last pope to do so was Gregory XII in 1415. Gregory acted to end the wrenching and violent Great Schism of the Roman Catholic Church, when more than one man claimed St. Peter's throne.
What's happening today is completely different; no one is fighting over the chair.
Yet Benedict's decision has resulted in hand-wringing over the unprecedented-in-modern-times specter of two men in white cassocks living, figuratively speaking, under the same Vatican roof: newly appointed Pope Francis and Pope Emeritus Benedict.
And now that Francis prepares to move over to the papal apartment, and Benedict into a refurbished monastery in the back yard, the odd relationship is piquing new interest,
Benedict may yet prove an annoying second-guesser, looking over Francis' broad shoulders.
So far, though, the 85-year-old German prelate has stayed almost completely out of sight since Feb. 28, when he flew in a helicopter from Vatican City to the papal summer residence, Castel Gandolfo, officially ending his papacy.
No evidence has emerged that he exerted undue influence over the election of his successor in the conclave, the secret meeting of cardinals in the Sistine Chapel.
That, despite the appearance of Benedict's longtime personal secretary, Archbishop Georg Gaenswein, in some of the sessions before the gathering.
(The Italian press quickly labeled Gaenswein "the eyes of Benedict.")
On Saturday, the Vatican announced that Pope Francis on March 23 will travel by helicopter to Gandolfo, just south of Rome, to pay his first visit to his predecessor.
They will have lunch. It will be four days after Francis' scheduled inauguration on Tuesday and 10 days after his election.
Francis called Benedict shortly after he was named the church's 266th pontiff and publicly saluted him in his first appearance as pope on the main balcony of St. Peter's Basilica before tens of thousands of people.
But he has frequently referred to him, not as pope emeritus, the title Benedict chose for himself, but as bishop, technically a lower position.
So many things about the new pope, at least in appearance and symbols, represent a marked departure from Benedict: the more simple clothing, the warmth and open laughter, the more casual speech.
Francis, as Argentine Cardinal Jorge Mario Bergoglio, came in second to the then-Cardinal Joseph Ratzinger in the 2005 conclave that produced Pope Benedict.
Since the heavy wooden doors of Castel Gandolfo closed behind him signaling the official end of his papacy, Benedict has been viewed once, thanks to Italy's persistent, eagle-eyed paparazzi.
In an Italian magazine called Chi, or Who, roughly an equivalent of People magazine, Benedict can be seen strolling through the castle's gardens with Gaenswein.
The emeritus pope is dressed in a white coat and a white hat that resembles a baseball cap.
Gaenswein, who participated last week in the Mass opening the conclave in his capacity as prefect of the papal household, told other prelates that his boss was watching the events on television.
"Gaenswein assured us Benedict is doing well and following events attentively," Vatican spokesman Father Federico Lombardi said. The Italian press is now suggesting he may be the go-between who conveys Benedict's secret papers over various Vatican scandals to Francis.
At the least, he seems to be regarded as a proxy for the former pope.
On Friday, during Francis' first session as pope with all of the cardinals, he warmly greeted each with embraces and intimate words.
At his side was Gaenswein. Many of the cardinals, after saluting their new pope, made a beeline for Gaenswein.