The new pope should be called Francis, not Francis I, the Vatican clarified yesterday.
Father Federico Lombardi, the Vatican spokesperson, remarked that the new pontiff was presented to the world with these Latin words: "Cardinalem Bergoglio, qui sibi nomen imposuit Franciscum " (Cardinal Bergoglio, who takes for himself the name of Francis).
The word "Primum" (the first), wasn't added.
"It will remain Francis until a successor calls himself Francis II," Lombardi said.
Bergoglio's decision to become the first pope ever to be known by the name Francis is almost unprecedented.
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Before him, the last pope to assume a name which wasn't already used by his predecessors was Landus (913–914). He reigned only six months during the period known as the saeculum obscurum (the dark age) when the papacy was in complete decline.
More recently, Albino Luciani combined two familiar names for popes, making the unused name of John Paul I for what would be a short-lived, 33-day papacy in 1978.
He was the first pontiff to intentionally add "the first" to his name - a move that was considered a formal error.
Until the first millennium, popes were called by their first plain names. An exception was the 6th century Mercurius, who was the first to pick a papal name. Rather than taking the papacy with the unappropriate name of a pagan god, he chose the name John II.
But the ordinal numbers weren't added to his name. The custom was that a second pope of the same name was called by the term junior and the third, if there were three, secundus junior. Thus, Pope Gregory II was known as Pope Gregory, Jr., while Pope Gregory III as Pope Gregory Secundus, Jr.
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As the system was too confusing, in the eighth century, an ordinal number was appended to the pope's name. Ordinal numbers became common only under Leo IX (1049–54) papacy.
Even today, the ordinal number is omitted in the solemn papal signature.
Since the 11th century, only two popes - Julius II (1503-13) and Hadrian VI (1522-23) - have refrained from changing their names.
John remains the most popular papal name in the history of the Catholic Church, followed by Gregory, Benedict, Clement, Innocent, Leo, and Pius.
Apart from Landus, John Paul I and Francis, other popes may have wished to pick a unique name, but their choice was considered incongruous or unappropriate.
It is said that John Paul II, born with the name Karol Wojtyla, had initially chosen the name Stanislaw, out of respect for the patron saint of his native Poland. The cardinals would have dissuaded him, as the name did not belong to the Roman tradition.
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In other cases, the chosen name, even if was previously used, wasn't just considered appropriate.
The vain Pietro Balbo, who became Paul II, wished to adopt the name Formosus II for his election in 1417. Meaning "beautiful" in Latin, the name wasn't however the best one to invoke as it would have reminded the so-called Cadaver Synod, where Pope Formosus I, exhumed nearly a year after his death, was put on trial by his successor Stephen VI.
The rotting corpse, clothed with the pontifical vestments, was seated in the papal throne, put on trial and condemned. Three of his fingers were ripped off and he was tossed into the Tiber river. Retrieved by a monk, Formosus' body was reinterred in St Peter's Basilica at the death of Stephen VI.
The last pontiff to shock the church was John XXIII (1958-63), the "Good Pope." In chosing his name, he went back to the Middle Ages. Many of the previous Johns had been disreputable, and it wasn't even clear how many of them there had been.
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The name Francis taken by Bergoglio is another stunning and bold choice, according to Vatican analyst John Thavis.
Picked in a reference to Saint Francis of Assisi, the most iconic saint in Catholic tradition, it symbolizes poverty, humility and simplicity.
"What has made this pope an early hit is the sense that Francis is more than a name, but rather a statement about the kind of pope he wants to be," Thavis wrote on the National Catholic Reporter.
Image: St. Francis of Assisi, the inspiration for the new pope's name. Credit: José de Ribera (1591–1652)