Pope Benedict is fighting the worst crisis of his papacy, but his problems are only the latest in a long history of controversies and intrigue in the headquarters of the Roman Catholic Church.

The "Vatileaks" scandal, in which the pope's private papers are alleged to have been pilfered by his own butler, pales in comparison to the scandals of centuries past when popes were accused of violence, nepotism and sexual excesses...

Although it is rare, leaking confidential documents is nothing new. Secret papers from the First Vatican Council of 1869-1870, which defined the doctrine of papal infallibility, ended up in German newspapers.

A highly sensitive papal commission report approving artificial birth control was leaked in 1967, a year before Pope Paul VI rejected its findings and issued the encyclical Humanae Vitae upholding an earlier ban on contraception...

In recent decades, the culture of secrecy helped mask the clerical sexual abuse of minors and the quiet reassignment of predator priests. It has also prompted charges that the Vatican bank laundered money and secretly funded projects abroad.

But all this is nothing compared to more ancient scandals.

In the 15th and 16th centuries, the Renaissance popes bribed their way into office, openly kept mistresses and families and appointed young nephews as cardinals.

Alexander VI, whose pontificate from 1492 to 1503 is generally agreed to have been the worst ever, was said to have presided over more orgies than Masses.

He came from the notorious Borgia family, who have been accused of adultery, rape, incest and murder. Alexander is said to have died from eating a poisoned apple.

Sixtus IV built the Sistine Chapel and the Vatican archives during his 1471-1484 pontificate, but also made six of his nephews cardinals and was involved in a murder plot.