How one Ancient Greek thinker revolutionized math — and possibly started a cult

Most people don’t remember math class, but they do remember Pythagoras. Greek philosopher and mathematician, he is credited with one of the handiest formulae any school student could know:

A squared plus B squared equals C squared equals all right-angle triangle mysteries solved.

Intoned so often as to be drilled into your memory for years after you leave the hallowed halls of learning, it is almost like a prayer or a spell.

Pythagoras would have loved that. As with most school lessons, the devil is in the details of what your teacher did not tell you about Pythagoras. When he wasn’t writing geometry proofs, he was a cult leader whose followers believed in reincarnation, loved animals, and despised beans.

Yet 2,512 years after Pythagoras was born, we still don’t quite know what he or the Pythagoreans believed. But there are some wild theories… Let’s dive in.

Cults and extreme beliefs fascinate us because we are all susceptible to their pull. Cult Week explores these stories — and the liminal spaces between the real and the imaginary.

WHAT DO WE KNOW ABOUT PYTHAGORAS?

The short answer is very little. The first biography of the famed mathematician was written 700 years after his death.

“The habit of writing books was still in its infancy in Greece when he was alive,” Philip Thibodeau, a Classics professor at Brooklyn College, tells Inverse.

Bereft of first-hand facts, rumors abound. But historians do agree on some key details: Pythagoras was born circa 562 BCE on the then-Greek island of Samos. He eventually settled in Croton, a Greek city in Southern Italy, where he gave lectures and married a local woman, Theano. In his 60s, he moved to Metapontum in the countryside, where he probably perished during an invasion. He was survived by a daughter, a few sons, and his cult.

In Croton, Pythagoras’ lectures gained a loyal following and even a school. Some historical accounts written long after his death suggest the community had severe entry requirements, like enduring years of silence to hear Pythagoras lecture from behind a curtain. Only a select few were allowed to ‘see’ him.

“To protect their number philosophy, the cult would kill.”

Members had to share their belongings, bring their families, and follow esoteric rules. Pythagoreans couldn’t wear white, wool, or rings. They avoided excess, sex (mostly), and picking up crumbs. It was taboo to write Pythagoras’ teachings down or tell non-followers about them. If there was thunder, Pythagoreans had to touch the ground.

Pythagoras taught ethics, law, astronomy, and, obviously, math. Reality, he said, is mathematical, and numbers can explain everything. Math led to happiness.

Other historians aren’t convinced that what Pythagoras had was a cult, however. “I would argue that he did not found a school,” Thibodeau says. “Instead, he presented his life and the life of his family as a model for imitation for the rest of the city.”

Meet the Pythagoreans

Stories about Pythagoras and the Pythagoreans should be treated with skepticism. One bizarre tale referenced in many books about his life, like The Cult of Pythagoras, recounts how Hippasus, a Pythagorean who may have shared the community’s secrets or suggested numbers aren’t rational, was sentenced to death by drowning by Pythagoras. In the book Zero: The Biography of a Dangerous Idea, science journalist Charles Seife writes: “To protect their number-philosophy, the cult would kill.”

In Divine Harmony, another book about Pythagoras’ life, one apocryphal tale recounts: “Once, upon seeing a dog be severely beaten, he rushed over and restrained the dog’s owner, saying: ‘You must stop this. I know from the sound of his cries that within the soul of this animal is my late friend Abides.’” Pythagoras believed in transmigration — the idea that souls of the dead enter a cycle of reincarnation, moving up and down the ranks of animals and humans. Some histories suggest Pythagoras believed his soul was the Trojan hero Euphorbus’ or perhaps related to the Greek gods Apollo and Hermes.

Pythagoras loved animals and encouraged his followers to become vegetarian — but no beans. Some accounts suggest Pythagoreans believed beans cause gas and irrational thinking or look like the gates of hell or people. Others think Pythagoras had a fava bean intolerance. There’s a story Pythagoras whispered his concerns about beans to an ox, which stopped eating them. He also apparently told a bear to stop hurting people, and, allegedly, it did.

Pythagoras adopts supernatural abilities throughout the tales of his life. He calmed stormy waters, ended a pandemic, visited the underworld, and talked to gods and demons.

Most of these are likely not true. But it’s fascinating which yarns have endured over millennia — and how stories of spiteful drownings and irrational beans contribute to the theory Pythagoras led a cult.

In old age, Pythagoras dabbled in prophecies and magic. “He was a religious man, a holy man,” Thibodeau says. But “he did not surround himself with the kind of group we would call a cult.” There’s no tangible, contemporary evidence of a cult of devotees to Pythagoras in Croton, although there were at least a few people who could be called his followers.

WHO WERE THE PYTHAGOREANS?

People assume the Pythagoreans were around at the same time as Pythagoras. Others believe the community grew after his death around 495 B.C.E. — a cult without a leader.

The Pythagoreans claimed their teachings came from Pythagoras, but historians don’t know if that’s true. We know they abstained from sex as much as possible, believed in education for all, and lived according to the will of the gods and nature.

“It’s clear these Pythagoreans were doing essential and highly original work.”

These practices were not unusual for the period. The Pythagoreans had a positive influence, allowed women to join, and wrote some of the first Greek-language books on metaphysics, geometry, music, astronomy, and medicine. “We only have little bits and pieces of these books,” Thibodeau says. “But it’s clear these Pythagoreans were doing essential and highly original work.”

Thibodeau suggests the Pythagoreans were not so much a cult as a think tank. “Look at the scientific side of their work and the research and design team at a place like Apple or Google. You picture a number of talented, obsessed individuals pushing the bounds of knowledge.”

Similarly, the Pythagoreans were secretive. But they were also radicals and people who likely had power and influence. “They were not totally underground,” Thibodeau says. “The Pythagoreans interfered with local politics enough to provoke a deadly backlash.”

We don’t know why or how the Pythagoreans petered out. Phillip Horky, a professor of ancient philosophy at Durham University, tells Inverse some accounts involve attacks by Greeks envious of the Pythagoreans' influence over the government. Others document attacks by Italians in the region of Croton. And more still hint at “a kind of civil war,” Horky says. “Possibly between Pythagorean aristocrats and Pythagorean democrats.”

CULT OR NOT?

It’s thrilling to believe the Pythagoreans’ cult-like rites led to their doom. One tall tale even suggests Pythagoreans were attacked because they refused to flee through a bean field. But most accounts suggest the Pythagoreans posed a political threat that ultimately wasn’t tolerated.

The Pythagoreans tried to regroup later, but it didn’t go anywhere. “These efforts did not last long,” Thibodeau says. “The community of Pythagoreans faded away.”

Yet Pythagoreanism survived and thrived. Its influence can be seen in “traditions of Byzantine, Arab, and Latin intellectualism in the Middle Ages, those of European Early Modernity, and what lies beyond, up to the present day,” Horky says. Just go to your local modern art gallery. Pythagoreanism lies “particularly in the modernist movement,” he says. “Which took the fundamental Pythagorean idea that ‘all is number’ seriously.”

Whether Pythagoras led a cult or just had some compelling and popular ideas has been subject to debate for centuries. Historians may never know if any accounts of his life and the Pythagoreans are true or even if his famous theorem deserves his name — Ancient Babylonians may be more deserving.

We do know Pythagoras was influential, and his legacy is still strong thousands of years later.

“He was undoubtedly a very charismatic individual, a very effective speaker, a very knowledgeable man, one with reformist instincts and proto-scientific and mystical facets to his life,” Thibodeau says. “But he was not the leader of a cult per se during his lifetime.”

Cults and extreme beliefs fascinate us because we are all susceptible to their pull. Cult Week explores these stories — and the liminal spaces between the real and the imaginary. Check out our hub to read more stories about cults and extreme beliefs.