Truth about Pythagoras.
It has always been difficult for me to decide about Pythagoras. Well till now. We all learned Pythagoras theorem in school and it is generally the first time we encounter a "proof" and it is all quite fascinating. When told that Pythagoras was the first to prove this theorem, it is hardly surprising that we are filled with respect for him. We are also told that he was indeed the first to introduce the notion of proof and was the precursor to later day trend setters like Euclid and Archimedes. And for those of us pursuing mathematics, Pythagoras is indeed a father figure.
But then you start reading independently and come across stuff saying that Pythagoras did not contribute much to mathematics. Then you console yourself saying that most of what goes under the name of Pythagoras was the work of "Pythagoreans", members of the secret society which was founded by Pythagoras.
Well, even that is dubious. Indeed, it is established quite well now that Pythagoreans were just a secret group created to achieve certain political ends, and genuine mathematical contribution from them was tiny. This history is very well summarized in this article in London Review of Books by M.F. Burnyeat.
Pythagoras was a political boss who managed to take control of parts of southern Italy through his secret society. Much of his commonly told story was made up almost two centuries after his death.
[T]he origins of the traditional picture of Pythagoras are to be sought, not during the sixth century BC, when he lived and fought his political battles, not during the fifth century, when democratic forces ousted his followers from power in various cities of southern Italy, but late in the fourth century. That was when Speusippus and Xenocrates, the dominant figures in Plato’s Academy, sought to devise ancient authority for certain aspects of their late master’s philosophy. Theirs was a conscious construction whereby Pythagoras became the apostle of mathematics and a highly mathematising philosophy, full of anticipations of Platonic metaphysics.
Starting from this Burnyeat recounts the actual story of Pythagoras and his society. He also mentions some very interesting details about Pythagoras's secret society.
It is amply clear that whatever Pythagoras and his followers were doing it was not laying the foundations for systematic and rigorous development of mathematics.