 It is in this latter role that he is connected with the split between two groups in ancient Pythagoreanism, the acusmatici (who emphasized rules for living one’s life, including various taboos) and the mathêmatici (who emphasized study of mathematics and the natural world). Each group claimed to be the true Pythagoreans. Our knowledge of this split comes from Iamblichus, who unfortunately presents two contradictory versions, with the result that Hippasus is sometimes said to be one of the mathêmatici and sometimes one of the acusmatici. Burkert has convincingly shown that the correct version is that reported by Iamblichus at De Communi Mathematica Scientia 76.19 ff. (1972a, 192 ff.). According to this account, the acusmatici denied that the mathêmatici were Pythagoreans at all, saying that their philosophy derived from Hippasus instead. The mathêmatici for their part, while recognizing that the acusmatici were Pythagoreans of a sort, argued that they themselves were Pythagoreans in a truer sense. Hippasus’ supposed innovations, they said, were in fact plagiarisms from Pythagoras himself. The mathêmatici explained that, upon Pythagoras’ arrival in Italy, the leading men in the cities did not have time to learn the sciences and the proofs of what Pythagoras said, so that Pythagoras just gave them instructions on how to act, without explaining the reasons. The younger men, who did have the leisure to devote to study, learned the mathematical sciences and the proofs. The former group were the first acusmatici, who learned the oral instructions of Pythagoras on how to live (the acusmata = “things heard”), while the latter group were the first mathêmatici. Hippasus was thus closely connected to the mathêmatici in this split in Pythagoreanism but ended up being disavowed by both sides. For an attempt to further characterize the mathêmatici see Horky 2013.