Coming up with a definitive list of the richest people of all time is almost impossible, thanks to the difficulties that arise with comparing different currencies and adjusting for inflation over thousands of years. But these 11 men were up there in the 0.001 percent of their time—and they were all just a little bit bonkers.

1. Jakob Fugger, March 6, 1459 – December 30, 1525

When a guy goes down in history with the nickname “The Rich,” you know he was the wealthiest person on the block. Jakob the Rich was a German merchant who made his fortune through textiles, mercury, and cinnamon. He was so minted that he loaned money to the Vatican, and held considerable control over the Holy Roman Empire. And Jakob’s business methods were so controversial that Martin Luther himself spoke out against him.

2. Marcus Licinius Crassus, ca. 115 BC – 53 BC

Wikimedia Commons

Years before he ruled Rome with Julius Caesar as part of the first Triumvirate, Marcus Licinius Crassus found himself in political hot water, and his fortune was seized. Eventually he got a bit of his power back, but not his money—so he took to seizing the property of criminals who had been put to death. If no rich criminals were up for execution any time soon, he would accuse random rich guys—just to confiscate their stuff. Crassus believed in laws, but not when they applied to him; he is even reported to have seduced a Vestal Virgin, an act so taboo he should have been put to death. But Crassus managed to talk his way out of it.

3. Musa I, c. 1280 - c. 1337

Wikimedia Commons

Musa, king of Mali in the early 1300s, decided one year to make the Islamic Hajj to Mecca. His journey required a retinue of 60,000 people in addition to 12,000 slaves. Everything that wasn’t actually covered in gold was transporting gold, and the entire group was reportedly carrying items worth over $400 billion in today’s money. Musa spent so much of his cash during his stopover in Egypt that it affected the national economy, and the country took years to recover.

4. Mir Osman Ali Khan, April 6, 1886 – February 24, 1967

Wikimedia Commons

Ruler of an Indian state from 1911-48, the Khan was loaded. Time even put him on their cover in 1937, proclaiming him the richest man in the world. It wasn’t hard to see why: The Khan owned his own mint, where he literally printed himself money. But he also had access to more solid forms of wealth. He was a great collector of jewelry and precious stones, amassing a collection that make Elizabeth Taylor’s famous gems look like Cracker Jack prizes. One notable stone was the Jacob diamond, believed to be the seventh largest in the word, and recently valued at $150 million. The Khan used it as a paperweight.

5. Heshen, 1746 – February 22, 1799

Wikimedia Commons

Heshen has the dubious honor of being remembered as the Chinese court's most corrupt official. Noticed by the Emperor at age 25, within a few years Heshen was given control of all of the country’s finances, and he used them to make himself rich: he amassed a huge art collection, thousands of priceless jewels and literally thousands of barrels full of gold and silver pieces. He stored all of this stuff in his numerous houses; between them, he had more than 3000 rooms.

6. Alan Rufus, c. 1040 – 1093

Wikimedia Commons

When a Norman named William was getting ready to launch an attack on England, he needed some good men to help him. It must not have been easy to get people to risk their lives and fortunes when you have a nickname like the Bastard. But Alan Rufus did sign up to follow William, and it worked out very well for both of them. The Bastard became the Conqueror and Rufus became the richest man in British history. In return for helping him win the throne and putting down a rebellion in the north of the country, William gave Rufus some 250,000 acres of land around England. And all he had to do was decimate the population of Yorkshire to get it.

7. Cornelius Vanderbilt, May 27, 1794 – January 4, 1877

Wikimedia Commons

A true American success story, the first of the Vanderbilt tycoons left school at 11 to work on a ferry. By middle age, Cornelius Vanderbilt owned most of the ferries in the northeast—he even loaned boats to the Union Navy during the Civil War. Eventually, Vanderbilt went into railroads, where he made his real money. At its height, his income was more than 1 percent of the entire country’s GDP. But while he may have been one of the richest men in the country, Vanderbilt was not welcome in society. Coming from such a poor background, he was considered very uncouth by Victorian society, and his affairs with prostitutes did not help matters. His sons had to wait until after he died to start building new fashionable mansions and ingratiating themselves with old money families.

8. Andrew Carnegie, November 25, 1835 – August 11, 1919

Wikimedia Commons

One of the richest men of all time was also the greatest philanthropist of all time. Andrew Carnegie famously gave away almost all of his wealth, but it was the people who wouldn’t take his money that make him stand out. After the Spanish-American War, the U.S. purchased the Philippines from Spain for $20 million. Incensed at what he saw as unnecessary American imperialism, the shipping magnate offered the Asian country $20 million of his own money so they could buy their country back. Carnegie's offer was declined.

9. Nicholas II, May 18, 1868 – July 17, 1918

Wikimedia Commons

The last of the Romanov rulers doesn’t just go down as possibly the richest monarch of all time, but also as the richest saint of all time, since after his death his family was canonized by the Russian Orthodox Church. The Emperor’s wealth was invested in all the standard places when he was alive—palaces, jewelry, art, gold—and after his death, most of his money and possessions were seized by the people who shot him. But some of Romanov’s nicest jewelry is now in the possession of the British royal family. There are rumors that when minor members of the Russian royal family fled the country to save their lives, they were forced to sell off the jewelry they managed to snag to fund their new lives.

10. John D. Rockefeller, July 8, 1839 – May 23, 1937

Wikimedia Commons

When your contemporaries include two of the other people on this list, it's really something to be the richest man in America. Rockefeller may have been competing with Vanderbilt and Carnegie, but he was the first man in U.S. history to amass a fortune of $1 billion. Rockefeller made his money by controlling 90% of all the oil and gas in America for decades, until the government decided they better do something about monopolies like Standard Oil. Rockefeller attributed all his success to God, and even when his net worth was more than 1.5 percent of the U.S. GDP, he taught Sunday School at his local church and even acted as its janitor as necessary.

11. Cosimo de' Medici, September 27, 1389 – August 1, 1464

Wikimedia Commons

Cosimo came from one of the most dysfunctional and powerful families in European history, thanks in no small part to their great wealth. While his relatives were busy getting elected Pope, throwing prostitute parties, and marrying into royal families, Cosimo controlled the business end of things. Despite never running for office himself, he was “king in all but name” of Florence. Like the rest of his family, he spent lavishly—his personal obsessions were art and the beautification of his hometown because, as he said, people would always remember him for it. He also said that while he had spent his entire life making and spending money, spending it was much more fun. You have to wonder who was paying for all those prostitute parties.