Siren,
Here is the link to look at.....Wikipedia explains it rather well...according to the prophecy the next pope will lead his people thru tribulations and Rome will be destroyed then shall the Fearful Judge judge the people. This prophecy is attributed to St Malachy. Many Catholic scholars debunk it, but we will all soon find out if its bunk or not....Ratzinger is already in his 80's and will probably only reign at most another decade.
http://en.wikipedia.org/wiki/Prophecy_of_the_Popes