The Most Brutal Medieval Monarchs

• Royal Title: Temujin, Great Khan of the Mongol Empire
• Most Brutal Moment: While carving out a massive empire that stretched across millions of square miles, Genghis Khan and his nomadic Mongolian soldiers took millions of lives. The Mongols once ended an estimated 1.2 million lives while sacking a single city. That's right, over 1 million people in only one battle.  In fact, one commentator reported that the Great Khan vanquished so many enemies that their bones formed mountains and the dirt became oily with human fat.

Some of his bloodier moments include using young men as human shields and organizing mass rapes. The latter event probably resulted in many children, making Genghis Khan a direct ancestor of 16 million people today. 

• Royal Title: Galeazzo Maria Sforza, Duke of Milan
• Most Brutal Moment: A master torturer and true evil mastermind, Galeazzo Maria once chopped off a rival's hands and ended a poacher by making him swallow an entire hare.

This 15th-century duke of Milan came by his brutal personality honestly. The surname of his warlord-turned-noble family, Sforza, means "force" in Italian. One contemporary writer recorded how Galeazzo Maria, upon asking a priest how long he would reign in Milan and being told only 11 years, stuck the good father in jail with just a little bit of food. As the story goes, "The man survived on these things, even getting to eat his own excrement, for twelve days. Then he died." Galeazzo Maria was also accused of organizing group assaults on women and dosing his own mother.

• Royal Title: Godfrey, King of Jerusalem
• Most Brutal Moment: The Siege of Jerusalem in 1099.

A French nobleman-turned-king of Jerusalem during the First Crusade, Godfrey, along with thousands of other men, marched on the Levant to take land that wasn't theirs in the name of religion. During the Siege of Jerusalem, the final battle for the Holy City, the Franks were savage, burning a number of Jews alive and trampling those seeking sanctuary. The chronicler Fulk of Chartres described the scene: "Indeed, if you had been there you would have seen our feet colored to our ankles with the blood of the slain. But what more shall I relate? None of them were left alive; neither women nor children were spared."

• Royal Title: Ferdinand I, King of Naples
• Most Brutal Moment: Slaying his rivals and building a "museum of mummies" with their remains in his palace.

Born the illegitimate son of a Spanish monarch, Ferdinand enjoyed keeping his deceased enemies around. Once, he invited some French "pals" (AKA agents of his rival to the throne of Naples) to dinner. After they ate, he then imprisoned others for 30 years, even shoving one guy out of a window to his demise. Some were propped up in a mock banquet at Castel Nuovo; the bodies were pickled and turned into mummies, then redressed to look lively.

• Royal Title: Olaf Tryggvason, King of Norway
• Most Brutal Moments: A Viking warrior par excellence, Olaf wasn't afraid of getting his hands dirty - and bloody - when it came to slaying pagans and the treacherous (he once beheaded a slave who took out a royal rival for him). 

In the 13th and 14th centuries, Olaf began to appear in poems as the slayer of a man named Raud, a determined follower of Thor. Despite Raud's best magical efforts, legend has it that Olaf's Christian faith dominated, but when Raud refused to accept Christ, Olaf forced a snake into his mouth using a red-hot iron. The serpent went through Raud's neck and ended him. Olaf took Raud's gold, dispatched his followers that wouldn't convert, and brought those that would be baptized into his fold.

• Royal Title: Henry VIII, King of England and Defender of the Faith
• Most Brutal Moment: Arguably still a medieval monarch on the edge of the Renaissance, Henry VIII did some pretty awful things. Probably his worst misdeed was engineering the demise of two of his six wives (Anne Boleyn and Catherine Howard).

Henry burned a number of "heretics" at the stake, including his own friend Sir Thomas More. Although Henry himself didn't lead his forces at the Battle of Flodden in 1513, this conflict was a tragedy for the invading Scots - including Henry's own brother-in-law, James IV, who perished there, along with an estimated 10,000 soldiers. By this time, his bloodthirsty ways had truly become a family affair.