Pythagoras, a Greek mathematician and philosopher, is best known for his work developing and proving the theorem of geometry that bears his name. Most students remember it as follows: the square of the hypotenuse is equal to the sum of the squares of the other two sides. It's written as: a ^{2} + b^{2} = c^{2}.

### Early Life

Pythagoras was born on the island of Samos, off the coast of Asia Minor (what is now mostly Turkey), about 569 BCE.

Not much is known of his early life. There is evidence that he was well educated, and learned to read and play the lyre. As a youth, he may have visited Miletus in his late teenage years to study with the philosopher Thales, who was a very old man, Thales's student, Anaximander was giving lectures on Miletus and quite possibly, Pythagoras attended these lectures. Anaximander took a great interest in geometry and cosmology, which influenced the young Pythagoras.

### Odyssey to Egypt

The next phase of Pythagoras's life is a bit confusing. He went to Egypt for some time and visited, or at least tried to visit, many of the temples. When he visited Diospolis, he was accepted into the priesthood after completing the rites necessary for admission. There, he continued his education, especially in mathematics and geometry.

### From Egypt in Chains

Ten years after Pythagoras arrived in Egypt, relations with Samos fell apart.

During their war, Egypt lost and Pythagoras was taken as a prisoner to Babylon. He wasn't treated as a prisoner of war as we would consider it today. Instead, he continued his education in mathematics and music and delved into the teachings of the priests, learning their sacred rites. He became extremely proficient in his studies of mathematics and sciences as taught by the Babylonians.

### A Return Home Followed by Departure

Pythagoras eventually returned to Samos, then went to Crete to study their legal system for a short time. In Samos, he founded a school called the Semicircle. In about 518 BCE, he founded another school in Croton (now known as Crotone, in southern Italy). With Pythagoras at the head, Croton maintained an inner circle of followers known as *mathematikoi *(priests of mathematics). These mathematikoi lived permanently within the society, were allowed no personal possessions and were strict vegetarians. They received training only from Pythagoras, following very strict rules. The next layer of the society was called the *akousmatics*. They lived in their own houses and only came to the society during the day. The society contained both men and women.

The Pythagoreans were a highly secretive group, keeping their work out of public discourse. Their interests lay not just in math and "natural philosophy", but also in metaphysics and religion. He and his inner circle believed that souls migrated after death into the bodies of other beings. They thought that animals could contain human souls. As a result, they saw eating animals as cannibalism.

### Contributions

Most scholars know that Pythagoras and his followers didn't study mathematics for the same reasons as people do today.

For them, numbers had a spiritual meaning. Pythagoras taught that all things are numbers and saw mathematical relationships in nature, art, and music.

There are a number of theorems attributed to Pythagoras, or at least to his society, but the most famous one, the Pythagorean theorem, may not be entirely his invention. Apparently, the Babylonians had realized the relationships between the sides of a right triangle more than a thousand years before Pythagoras learned about it. However, he spent a great deal of time working on a proof of the theorem.

Besides his contributions to mathematics, Pythagoras's work was essential to astronomy. He felt the sphere was the perfect shape. He also realized the orbit of the Moon was inclined to Earth's equator, and deduced that the evening star (Venus) was the same as the morning star.

His work influenced later astronomers such as Ptolemy and Johannes Kepler (who formulated the laws of planetary motion).

### Final Flight

During the later years of the society, it came into conflict with supporters of democracy. Pythagoras denounced the idea, which resulted in attacks against his group. Around 508 BCE, Cylon, a Croton noble attacked the Pythagorean Society and vowed to destroy it. He and his followers persecuted the group, and Pythagoras fled to Metapontum.

Some accounts claim that he committed suicide. Others say that Pythagoras returned to Croton a short time later since the society was not wiped out and continued for some years. Pythagoras may have lived at least beyond 480 BCE, possibly to age 100. There are conflicting reports of both his birth and death dates. Some sources think he was born in 570 BCE and died in 490 BCE.

### Pythagoras Fast Facts

**Born**: ~569 BCE on Samos**Died:**~475 BCE**Parents**: Mnesarchus (father), Pythias (mother)**Education**: Thales, Anaximander**Key Accomplishments:**first mathematician

### Sources

Britannica: Pythagoras-Greek Philosopher and Mathematician

University of St. Matthews: Pythagoras Biography

*Edited by Carolyn Collins Petersen.*