Benedict XVI, however, is one of the rare popes who have departed for any reason other than death.
The last was 598 years ago, Pope Gregory XII, in 1415.
Pope Benedict’s decision reflects both the torrid pace of official life for a man who leads 1 billion Christians worldwide and indirectly, some believe, of reasons to elect popes of a younger age. Benedict was 78 when elected in 2005, the oldest pope at election since the 1700s.
His predecessor, John Paul II, was younger and reigned for 27 years, during a transformative era in world politics and in the way the Catholic Church influences culture.
As recently as the 19th century the popes wielded significant political authority because they headed the papal states, a part of what later became a united Italy.
Pope Benedict had to deal with an international scandal of sexual abuse by priests of children, nowhere more openly than in the United States, where lawsuits against the church as a corporation proliferated and led to huge monetary settlements paid to victims and their families in some cases.
The same behavior surfaces in many other religious organizations, but no one else has 25 percent of the U.S. population and roughly half all the 2 billion Christians worldwide.
Already, published lists of possible successors include names of cardinals from outside Europe – including Cardinal Timothy Dolan of New York, to names from Brazil and others from Africa and Asia. An election of a non-European would be unprecedented, but also an acknowledgment that Catholic growth, like that of many non-Catholic churches, is in the developing world.
The surprise of an unexpected resignation is no different from the retirements of beloved ministers and priests in non-Catholic congregations, but the magnitude is multiplied because no one living has ever experienced it within Catholicism.