From mistresses and illegitimate children to dance parties and harbored criminals, the Vatican has a shockingly dirty history.

While it's true that no one is perfect, the seven corrupt popes below were exceptionally unholy:

7. Pope Clement VII (Pope from 1523 to 1534)

Besides being indifferent to the Protestant Reformation (a reform movement in Europe when several denominations broke away from the Catholic church), Pope Clement VII became best known for flip-flopping between alliances with France, Spain and Germany, although he began to lean toward French political forces before his death in 1534 after eating a poisonous mushroom.

Clement was inclined to changing his political views to match those of whomever was the most powerful and wealthy at any given time. As a result of his wavering allegiances, Clement VII's critics, who included Charles V, compared him to a shepherd that had fled his flock, only to return as a wolf, according to "The Pontificate of Clement VII: History, Politics, Culture" (Ashgate Publishing, Ltd., 2005).

6. Pope Leo X (1513 to 1521)

Pope Leo X not only allowed, but encouraged worshippers to pay for their sins – literally. The corrupt religious leader was fond of putting prices on others' sins and requiring them to give him money in return for absolving their wrongdoings. Threatening that their souls would not be able to enter heaven if they didn't pay up, Leo X set sinner fines for crimes such as murder, incest and theft, "Pope Leo X: Opponent of the Reformation" (Compass Point Books, 2006).

Leo X was strictly against the Protestant Reformation, which was inspired by Martin Luther's argument against the church's unscrupulous methods of attaining funds based on people's fears of not getting into heaven, according to "Pope Leo X."

5. Pope Julius II (1503 to 1513)

Despite the clergy's sacred oath of celibacy, Julius reportedly had several mistresses and at least one illegitimate daughter (some sources indicate that he had two other daughters who died during childhood). In 1511, a council brought charges of lewd sexual acts against him, alleging that he was "a sodomite covered with shameful ulcers," according to Dr. Joe J. Payyapilly in "The Spirit of Holiness" (Xlibris Corporation, 2010).

Although he was a fan of the arts and collected ancient sculptures, he was apparently not a believer in the adage – good art takes time. Julius forced Michelangelo to complete the Sistine Chapel before he was ready to do so, according to "The Western Heritage" (Prentice Hall, 2000).

Michelangelo never got around to finishing Julius' tomb after the pope had died, according to "Christianity: the First Two Thousand Years" (Continuum International Publishing Group, 1997).

4. Pope Alexander VI (1492 to 1503)

Even though he was supposedly a celibate clergyman, Alexander VI romanced several mistresses, including Giulia Farnese (known as Julia the Beautiful), and fathered numerous illegitimate children with longtime mistress Vannozza dei Cattani (who was married at the time), according to "The Last Judgment," (Macmillan, 2009).

His hedonistic ways were so shameless that even as crime and violence overtook the streets of Rome, the pope busied himself with staging comedic plays, lavish banquets, masquerades and dance parties – paid for with the church's funds, according to "The Borgia Pope" (Kessinger Publishing, 2006). Possibly as backlash for his playboy lifestyle, rumors of Alexander VI arranging orgies began to surface, according to the 2006 book.

3. Pope Benedict IX (1032 and 1048)

Gaining power and wealth from an early age as a result of his family's ties to the church, Benedict IX essentially inherited the title of pope since he was the nephew of both Pope John XIX and Pope Benedict VIII. He was only 20 years old, but quickly developed a reputation as being "cruel and immoral," according to "The Rise of the Medieval World, 500 – 1300" (Greenwood Publishing Group, 2002).

In fact, in his third book of dialogues, Pope Victor III wrote of Benedict IX's "rapes, murders and other unspeakable acts. His life as a pope so vile, so foul, so execrable, that I shudder to think of it," according to "The Spirit."

Saint Peter Damian had similar things to say of Benedict IX, describing him as "feasting on immorality" and "a demon from hell in the disguise of a priest," who sponsored orgies and routinely partook in bestiality, according to "The Spirit." In his final act of corruption as pope, Benedict IX decided that he wanted to pursue marriage, so he sold his holy title to his godfather for 1,500 pounds (680 kilograms) of gold.

2. Pope John XII (955 to 964)

Attaining the title of pope at age 18, John XII was quickly deemed lazy and childish. Harsher accusations followed from his critics, who included priests and religious authorities.

The "Patrologia Latina," a collection of the writings by church leaders, lists the charges made against John XII, including that he invoked demons, murdered and mutilated men, committed arson and gambled, according to "A History of the Church in the Middle Ages" (Psychology Press, 2002). The church leaders also claimed that he “turned the papal palace into a whorehouse” by committing adultery with numerous women, including two widows and his own niece, as well as his father's long-term girlfriend.

His reign as pope ended in his late 20s when he died of a stroke while supposedly in bed with a married woman, according to "A History."

1. Pope Stephen VI (896 to 897)

Arguably the most unbalanced of this lists' unscrupulous popes, Stephen VI set out to get revenge on his predecessor, Pope Formosus, who he felt had wronged him – in spite of the fact that his nemesis was now dead. Stephen arranged a court date and ordered Formosus' nine-month-old corpse to be exhumed, dressed in sacred papal robes and propped up on a throne to be tried for his crimes. With a deacon answering on behalf of the deceased, Stephen raged and raved accusations of Formosus having had unfairly receiving the pope title at Formosus' skeleton.

The cadaver lost the trial, and Stephen declared Formosus' rule as pope void. He then chopped off the three fingers used to give blessings and ordered the body to be stripped of its robes and dumped into a cemetery for foreigners. Soon after, an earthquake struck Rome, destroying the papal basilica. The corpse was dug up once again and flung into the Tiber Rover, but a few compassionate people fished it out and gave Formosus a proper burial, according to "A History of the Church in the Middle Ages" (Psychology Press, 2002).

However, the macabre trial came back to haunt Stephen, as the earthquake's damage was taken as a sign from God. Rioting mobs of Formosus' supporters arrested Stephen and locked him in a dungeon, where he was later found strangled to death, according to "A History of the Church."

This article was provided by Life's Little Mysteries, a sister site to LiveScience.