 Hippasus is a crucial figure in the history of Pythagoreanism, because the tradition about him suggests that even in the fifth century there was debate within the Pythagorean tradition itself as to whether Pythagoras was largely important as the founder of a set of rules to follow in living one’s life or whether his teaching also had a mathematical and scientific dimension. Hippasus was probably from Metapontum (Aristotle, Metaph. 984a7; Diogenes Laertius VIII 84), although Iamblichus says there was controversy as to whether he was from Metapontum or Croton (VP 81), and he is listed under Sybaris in Iamblichus’ catalogue (VP 267). He is consistently portrayed as a rebel in the Pythagorean tradition, in one case a democratic rebel who challenged the aristocratic Pythagorean leadership in Croton (Iamb. VP 257), but more commonly as the thinker who initiated Pythagorean study of mathematics and the natural world.