It’s quite impossible to find a biography of Pythagoras. Not a good one, anyway.
You can find information on the Pythagorean theorem and on the group of his followers (Pythagoreans) that kept his ideas alive for centuries after his death, but there are few written records on the Greek philosopher and mathematician.
As a matter of fact, some people believe that all of the theories attributed to Pythagoras, including those regarding hypotenuse and the shape of the Earth, actually came from the brotherhood collectively and not from any one person.
What we do know is that Pythagoras lived in the sixth century B.C. and his followers were still active throughout the fourth century B.C.
Other Greek philosophers, such as Aristotle, commented widely on the group’s discoveries and advances.
No matter who, whether an individual or the group, is responsible, what they proposed was astounding for their time.
Pythagorean theories include the famous “the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides.”
They also reduced both music and astronomy to numeric patterns, and theorized that the planets, the Earth, and the moon all revolved around the sun.