The last pope to resign was Pope Gregory XII on 4 July 1415. Unlike today's resignation, Gregory's election and resignation occurred during a perilous crisis in the Church. Despite his resignation, a new Pontiff was not selected during Gregory's lifetime: Pope Martin V, was chosen at the Council of Constance (in Germany) on 13 November 1417- Gregory having died 18 October 1417.
It appears a conclave to select Pope Benedict XVI's successor will be held in March. Hence, we will have a new Roman Pontiff by Easter. Christ's Church is not and will not be in crisis.
I have convoked you to this Consistory, not only for the three canonizations, but also to communicate to you a decision of great importance for the life of the Church. After having repeatedly examined my conscience before God, I have come to the certainty that my strengths, due to an advanced age, are no longer suited to an adequate exercise of the Petrine ministry. I am well aware that this ministry, due to its essential spiritual nature, must be carried out not only with words and deeds, but no less with prayer and suffering. However, 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 barque 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. For this reason, and well aware of the seriousness of this act, with full freedom I declare that I renounce the ministry of Bishop of Rome, Successor of Saint Peter, entrusted to me by the Cardinals on 19 April 2005, in such a way, that as from 28 February 2013, at 20:00 hours, the See of Rome, the See of Saint Peter, will be vacant and a Conclave to elect the new Supreme Pontiff will have to be convoked by those whose competence it is.
Dear Brothers, I thank you most sincerely for all the love and work with which you have supported me in my ministry and I ask pardon for all my defects. And now, let us entrust the Holy Church to the care of Our Supreme Pastor, Our Lord Jesus Christ, and implore his holy Mother Mary, so that she may assist the Cardinal Fathers with her maternal solicitude, in electing a new Supreme Pontiff. With regard to myself, I wish to also devotedly serve the Holy Church of God in the future through a life dedicated to prayer.
From the Vatican, 10 February 2013
When he was named Pope at age 78 back in 2005, Joseph Ratzinger was one of the oldest popes in history at the time of election. His brother, Msgr. Georg Ratzinger, speaking to the media from his home in Regensburg, Germany, indicated that the Pope had been advised by physicians not to take anymore overseas trips. He also pointed to the increasing difficulty the Pope had in just walking, noting his brother's resignation was a "natural process." Msgr Ratzinger, who is his brother's confidant, indicated that Pope Benedict has been thinking about resigning for months. I think we will see more of this due to the age people are prone to live in our day and the unmitigated infirmity that comes along with old age.
Pope Benedict, Papa Ratzi, I love you, I will continue praying for you, specifically that God, in His infinite goodness, will grant you several years of peaceful serenity. Above all, thank you for your many years of faithful, creative, and inspiring service to the Church. In imitation of our Lord, you have been a good shepherd, or, hearkening back to your remarks on the day of your election, a faithful worker in the Lord's vineyard.