You all know about Pythagoras, the triangle guy? His brilliant theorem to calculate the lengths of the sides of a right-angled triangle is elegant, and unlike almost every other idea the ancient Greeks came up with (with apologies to Euclid) it turned out that he got it right first time. We still use his equation today, and it forms the basis of an entire branch of mathematics. It is fair to say that Pythagoras, more than any other ancient Greek, reaches into our calculators and our phones, our computers and our televisions, making our world work from 2,500 years ago. So can we say he was stone cold genius, end of story? Well, yes and no. Because when we ask whether you know about Pythagoras, we are betting that the answer is more accurately that you don’t.  You’ve heard of him, for sure, but what do you know about the man? You might have heard about the music of the spheres, perhaps the most poetic phrase ever applied to pure mathematics, but how about his thoughts of reincarnation, immortality, democracy, or fava beans? What about the home he made for himself in a cave, or the cult he fostered and taught his crazy own brand of philosophy, cautioning his followers against having too much sex? What about that time his wrestling buddy saved his life? And what, ultimately, do we know about the truth of any of this? For Pythagoras is one of those elusive figures who bridges the gap between reality and myth, a legend in his own lifetime and for ever afterwards as well. What, if anything, about his life is true? Can we unpick the man from the legend of Pythagoras? A Strange Man Possessed of Strange Ideas This much we think we know. Pythagoras was born around 570 BC on the island of Samos in the eastern Aegean Sea. He lived earlier than Socrates or Plato, earlier than Aristotle; these greats all drew from his thinking as one of the true founding fathers of philosophy. Of his education we know next to nothing, but we do know that aged around 40 he travelled to the city of Croton in southern Italy, where he would found his school. His teachings are discussed at extreme length in the writings of Aristotle, or at least we think they are. You see, Aristotle never actually mentions Pythagoras by name, but for many the descriptions are enough to confirm the link between the lessons and the earlier philosopher. It is thankful that Aristotle did write all this down, because for several key concepts his is the only detailed source. So, what was Pythagoras thinking? Well, if we don’t want to rely heavily on one or two sources the best place to start would be with metempsychosis: he believed in the immortal soul as something separate and distinct from the body. He went further, as well, teaching that when we die our souls are transferred to other bodies, an immortality of sorts inherent in reincarnation. One ancient writer even mentions the fact that Pythagoras claimed to be able to remember his previous incarnations, including that time he was the son of a god, and that other time he fought in the Trojan War. This takes the great man somewhat out of his “father of mathematics” brand and into an area of questionable reliability. Pythagoras certainly claimed to have lived spicy lives, as a courtesan or philosopher, something he shares with all the modern-day charlatans claiming the same. Nobody wrote down how Pythagoras thought metempsychosis was supposed to occur, but it appears to have been a cornerstone of his school. This would go some way to explaining the cultlike status this “semicircle” of followers attained: promise of life after death has ever attracted devoted believers, often simply because the alternative is not an easy thing to contemplate. His followers lived an odd life at the Pythagorean school. They started by committing to a vow of obedience to Pythagoras, and during their stay were denied much, living simply and according to his teachings.  There was also much secrecy. Initiates were taught a series of symbols which they swore never to divulge to outsiders. But it is perhaps in these secrets that the true genius of Pythagoras can be found, for he taught of the beauty and elegance in explaining the world around him, and the wider universe, through mathematics. He called it, at least in relation to the heavens, the “music of the spheres” and his body of work, of which the Pythagorean theorem is only the most famous, was indeed something far ahead of his time. He sought to explain the world as he saw it through mathematical equations, physical laws and proportions which governed reality, in just the same way as we do today. It would certainly be fair to say that Pythagoras was more entranced and wide-eyed by the idea than we are, which is understandable given he came up with a lot of it. But his brilliance lay in recognizing that the world could be explained without the need for divine involvement, but by understanding the underlying mechanisms. And this meant it could be predicted too. He was famed for practicing “prophecy” and while some use this fact to scoff at him, others see in this his understanding of the universe as ordered and consecutive. Aristotle said he was the first philosopher to practice mathematics, and in doing so he had hit upon the underlying mechanisms of reality. He may have let this go to his head, however. He is also said to have dressed all in white, to have worn a golden circlet, and to have abstained entirely from laughter. He also became convinced that he could talk to animals, persuading a bull not to eat fava beans, which he had decided were sacred. He had few friends, perhaps the most prominent being Milo of Croton, a wrestler who is said to have saved his life when the