Joseph Ratzinger

This is "Saint Paul's Joke" (2012, Amazon) -- several months before the publication, the Vatican requested two pre-publication copies ... one element of the book is the Prophecies that affect the church, and most notably, the prophecy of St Malachy -- an Irish archbishop, who, around 1140, predicted 112 popes before the end of both Rome and the Church. Benedict is the 111th.
There is the wording "Last but one" which confused those who tried to define who the last pope would be. The pope who will reign with a living ex-pope would indicate that is what Malachy saw. Either this individual will be PETER of ROME -- the label associated with the last pope, or the one who follows him will be. In either case, there will either be another earthquake in Rome ... or a terrorist attack on the scale of a Dresden bombing ... and Rome and the Church shall end.
Malachy also indicated it would be the Christian Judgement Day -- "Saint Paul's Joke" looks to the canonized letters of St Paul to determine the basis of that Judgement, and why Revelation indicates only Jews will be granted immediate salvation. Fortunately, we can count on Catholics being different from the Pontiff -- they are unlikely to contemplate "Saint Paul's Joke". Benedict's retirement might be an effort by the Church to circumvent Malachy -- and finally MAKE him wrong.

Look to March 25th -- it is a day that has significance in the life of Joseph Ratzinger

The last pope to resign willingly was Celestine V in 1294 after reigning for only five months, his resignation was known as "the great refusal" and was condemned by the poet Dante in the "Divine Comedy". Gregory XII reluctantly abdicated in 1415 to end a dispute with a rival claimant to the papacy.