History may show that the most significant decision during the papacy of Pope Benedict XVI may be his surprising decision Monday to resign on Feb. 28. In making that choice, Pope Benedict, 85, recognized that "strength of mind and body are necessary" in the modern papacy. Where once an aging pope could withdraw to "prayer and suffering," wrote Pope Benedict in his letter of resignation, today's rapidly changing world requires an engaged spiritual leader of the Roman Catholic Church.

"I have come to the certainty that my strengths, due to an advanced age, are no longer suited to (the) … ministry," wrote Pope Benedict.

This precedent may give future popes the freedom to step aside if they decide they too are no longer up to the task physically.

When the cardinals of the church gather to select the next pontiff some interesting dynamics will be at play. The German-born Cardinal Joseph Ratzinger was 78 when elected pope in April 2005, the most elderly new pope since 1730. It seemed his fellow cardinals were intent on assuring a short papacy after Pope John Paul II's 27-year reign, the second longest in history. The leaders of the church may well opt for a significantly younger successor.

There is also speculation whether the cardinals, given the church's decline in Europe, will for the first time select a pope from Latin America or Africa, where the faith is expanding. We suspect the cardinals will seek someone without taint from the sexual abuse scandals, a stain that the current pope was unable to avoid getting caught up in. While they will seek the guidance of the Holy Spirit, politics and practicality are always at play when the College of Cardinals gathers.

This is the first time since 1415 that a pope will be alive to see his successor chosen. In that year Gregory XII stepped aside to end a schism that had left the papacy in dispute.

Unfortunately, any successor is unlikely to change church theology on issues such as birth control, priestly celibacy and the role of women. The popes select the cardinals and both John Paul and Pope Benedict tended to appoint those who shared their conservative theology. Now they elect the next pope.