In the spring of 2009, Pope Benedict XVI stopped in Aquila, Italy, to pray at the shrine of St. Celestine V. The pope left his pallium -- a wool garment that resembles a yoke, symbolizing bonds between a shepherd and his flock — on this medieval pope’s tomb, noted theologian Scott Hahn of Franciscan University of Steubenville. Then, 15 months later, he visited a cathedral outside Rome to pray before the relics, once again, of St. Celestine V.

Few noticed Benedict’s actions at the time, wrote Hahn, on his Facebook page. So who was this saint? He was the elderly priest who, “somewhat against his will,” was elected pope in 1294. Before long, Pope Celestine V issued a decree allowing occupants of St. Peter’s throne to step down -- a step he then proceeded to take.

Looking back, it appears Benedict’s visit to shrines honoring this particular pope were “probably more than pious acts,” argued Hahn. “More likely, they were profound and symbolic gestures of a very personal nature, which conveyed a message that a pope can hardly deliver any other way."

This was a message consistent with the 86-year-old pope's stunning announcement this week -- days before the start of Lent -- that he would end his eight-year papacy on Feb. 28. Although it has been seven centuries since the voluntary resignation of a pope, this option remains in canon law and was affirmed by Pope Paul VI in 1975 and the Blessed John Paul II in 1996.

Benedict said he was thinking about the future of the papacy, not the past: "In today's world, subject to so many rapid changes and shaken by questions of deep relevance for the life of faith, in order to govern the bark of Saint Peter and proclaim the Gospel, both strength of mind and body are necessary, strength which in the last few months, has deteriorated in me to the extent that I have had to recognize my incapacity to adequately fulfill the ministry entrusted to me."

The Vatican Press Office noted these words were consistent with his thoughts in the 2010 book, "Light of the World." While it would be wrong to flee in times of trouble, Benedict said: "When a Pope realizes clearly that he is no longer physically, mentally, and spiritually capable of carrying out his role, then there is legally the possibility, and also the obligation, to resign."

Vatican leaders are planning for the election of a pope by Easter, thus creating a whirlwind of activity. Reactions, so far, have included:

* Comedy Central's Stephen Colbert -- an active Catholic -- quipped that "popes don't quit. God has a way of telling popes when it's time to retire. It's called death." Father James Martin, a Jesuit known as The Colbert Report chaplain, later tweeted that he should have told the comedian, "Pope Benedict XVI is raising the bar when it comes to giving things up for Lent."

* On the far doctrinal left, Catholics United noted: "The Catholic church hierarchy has been seen as an institution overly focused on issues of human sexuality, such as opposition to access to birth control and marriage equality. ... The next pope has a unique opportunity to radically shift the agenda of the church."

* Among journalists, "The Fix" blogger Chris Cillizza at The Washington Post tweeted: "Pope Benedict, following Sarah Palin's lead, resigns."

* This pope's departure drew several tributes from Protestant conservatives. Benedict reminded the world that humans are not mere machines, "collections of nerve endings, that spark with sensation when rubbed together," noted theologian Russell Moore of Southern Baptist Theological Seminary. The pope defended Down syndrome babies and Alzheimer's patients, as well as those "society wants to dehumanize with language: 'embryo,' 'fetus,' 'anchor baby,' 'illegal alien,' 'collateral damage,' and so on."

* Strategically, the key is that Benedict's "out of the blue" decision will do much to prevent the months or even years of political maneuvering that precede papal elections, wrote Jimmy Akin of Catholic Answers. It also helps that Benedict did not act in response to calls for his retirement, such as the campaign aimed at John Paul II.

At the same time, he noted, "advancing medical technology means increasingly long life spans with a longer period of frail health. ... Unless we get really wizard regenerative medical technology really soon, we're likely to have more popes in that kind of situation, and thus there are likely to be more resignations in the future."