The catholic pope announced his resignation:
Pope Benedict XVI on Monday announced he will resign on February 28, a Vatican spokesman told AFP, which will make him the first pope to do so in centuries.
The last pope to resign voluntarily was Pope Celestine V in 1294.He did not want to be pope in the first place. Celestine V gave his reasons as:
the desire for humility, for a purer life, for a stainless conscience, the deficiencies of his own physical strength, his ignorance, the perverseness of the people, his longing for the tranquility of his former life.
Benedict XVI said:
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.
A new pope is usually elected when the old one is dead and often not to his (assumed) liking. His resignation will allow Benedict to influence the election of his successor. That may be the real reason behind this surprizing step.
The Supreme Guidance Council of the Egyptian Muslim Brotherhood convened immediately and is thought to suggest the upcoming head of Al-Azhar, Abdul Rahman al-Bar, as its papal candidate. Vatican aids thought it unlikely that al-Bar would gather enough support in the Vatican to make it into the final selection.
The election of a pope is always a highly political process. Various states will try to push their favorite candidates and agendas. The ideal candidate though will not be considered. That would be a tall black African woman, married and with children.