Immediately after a newly chosen pope accepts his role, he faces the question: “By what name shall you be called?”
It's now taken for granted that whoever becomes pope will adopt a new papal name. In fact, almost half a millennium has elapsed since a pope used his birth name.
In the early centuries of the Church, however, popes did use their birth names. The concept of adopting a new papal name began in the year 533, when a priest named Mercurius was selected as pope and decided that it was inappropriate for the Bishop of Rome to have a name that honored the pagan god Mercury. So he cast aside his birth name and became Pope John II.
Though not much information remains of his two-year papacy, John II seems to have had a moral backbone, as he confined at least one philandering bishop to a monastery.
The second pontiff to adopt a papal name was Pope John III. Born as “Catelinus,” he was the son of a prominent member of the Roman Senate. His papacy lasted almost exactly 13 years (July 17, 561, to July 13, 574), which was no small achievement in that era. John III seems to have had good survival instincts. And during one especially tumultuous period, he performed his papal duties at a special location a few miles outside Rome.
No ensuing pontiffs adopted new names until the 10th century.
Born as “Octavian,” Pope John XII was clearly a well-connected young man when he was chosen pontiff around the age of 20 in the year 955. Despite having become the Bishop of Rome, “ecclesiastical affairs did not seem to have had much attraction” for him. Instead, he “passed his whole life in vanity and adultery.” After occupying the papacy in this way for eight-plus years, he died under unclear circumstances.
The fourth pope who adopted a new papal name was Pope John XIV. Born in the 10th century as Peter Canepanova, he was selected not by any clergy or popular vote, but by the sole discretion of Holy Roman Emperor Otto II.
When Otto II died soon after, John XIV lost his main (perhaps only) ally and was left both politically and physically vulnerable. An antipope soon swooped in to seize the papacy and imprison John XIV in the Castel Sant'Angelo, where he died of unnatural causes on August 20, 984. His pontificate had lasted all of eight months, including his period of captivity.
Born as Bruno of Carinthia in the year 972, Pope Gregory V was the son of a duke and was made pope by Holy Roman Emperor Otto III, who was his cousin. His pontificate began on May 3, 996, and ended almost three years later, with his sudden and suspicious death on February 18, 999.
Soon after the papacy of Gregory V, it became customary for incoming popes to adopt a new name. As a result, only two popes in the modern era have kept their birth names.
The first was Pope Adrian VI. The only Dutch pope in two millennia, he was born Adriaan Florensz Boeyens. A carpenter's son, he became a longtime theology professor and tutor to the future Holy Roman Emperor Charles V.
On January 9, 1522, he was selected as a compromise choice between quarreling factions of cardinals, many of whom then united in their resentment toward the new pope when it became clear he was actually serious about eradicating corruption and extravagant spending.
Adrian VI was a righteous pontiff who truly wanted to reform a Church mired in a quicksand of simony, indulgences, and opulence, as well as warring Catholic princes, a growing threat from the Ottoman Empire, and a nascent Protestant Reformation.
His biggest obstacle, though, were cardinals who wanted to continue living like Renaissance princes. Twenty months into his pontificate, he died on September 14 1523, at age 64 — exhausted, resented, and incorruptible.
The most recent pontiff to keep his birth name was Pope Marcellus II. Born in 1501 as Marcello Cervini degli Spannocchi, he was the son of an apostolic treasurer.
When his papacy began on April 9, 1555, Marcellus II was already feeling ill. He died of a stroke three weeks later.
With Marcellus II having had such a brief pontificate, we might wonder if keeping one's birth name was viewed as bad luck. Either way, no new pope has done it since.
