But even those cases, both in the 17th century, did not involve a breach of trust by a papal aide - the issue at the core of this Saturday's trial of papal butler Paolo Gabriele for stealing and leaking the pontiff's personal papers. 

One of the worst crises in Pope Benedict's papacy will play out in a small Vatican tribunal, where a three-judge panel will decide the fate of the 46-year-old Gabriele, whom the pope used to call "Paoletto" (little Paul) and who is now described in Vatican documents as "the defendant".

 

The case will put the inner workings of the tiny Vatican, the world's smallest state, in the type of media spotlight it usually strives to avoid.