How Do the Popes Get Their Names?

Thomas Vinciguerra, in the NYT (4-10-05):

One perk of being pope is that you can pick your own name. This wasn't always the case. Originally, popes kept their given names, but in 532, when a priest named Mercury assumed the throne, he discarded his pagan name in favor of John II. By the early 11th century, new names were the rule. Marcellus II, elected in 1555, was the last pope to keep his given name.

Various popes have rechristened themselves after apostles or other important church figures; many have taken names that project an image, like Pius, Clement or Innocent. Frequently, a pope will name himself for a distinguished predecessor: in 1831, Bartolomeo Alberto Cappellari became Gregory XVI because he particularly admired Gregory the Great (pope from 590 to 604) and St. Gregory VII (1073-85).

Among the 265 popes are 43 whose names have been used only once. The list includes Linus, Eusebius, Agatho, Sisinnius, Formosus, Romanus and the improbable Hilarius. It's unlikely that the next pope will choose any of these. It is also all but certain that he will not fashion himself Peter II, after the first pope, whose name is held sacrosanct.

Generally, modern popes name themselves in deference to a Holy Father who helped them rise through the church's hierarchy or otherwise shaped their careers. Hence, for the last few centuries, the same names have tended to recur.

From 1667 to 1774, 6 of the 12 popes were Clements; after them, 7 of the next 11 were Piuses. In fact, just six papal names - Clement, Pius, Benedict, Leo, Innocent and Gregory - account for every pope from 1590 to 1958, with only four 17th-century exceptions: Paul V, Urban VIII, and Alexanders VII and VIII.

When the reform-minded Angelo Giuseppe Roncalli became John XXIII in 1958, he signaled his break with centuries of tradition by adopting his father's name. In doing so, he also reached back more than 600 years to his papal namesake, John XXII (1316-34).